Revert `tests/testdata` changes and address flake8 issues

tests/testdata/wmt20-en-de-v0-res.json

-{"results": {"wmt20-en-de": {"bleu": 0.0, "bleu_stderr": 0.0, "chrf": 0.007148103038872972, "chrf_stderr": 9.594096858911254e-05, "ter": 1.0, "ter_stderr": 0.0}}, "versions": {"wmt20-en-de": 0}}
+{"results": {"wmt20-en-de": {"bleu": 0.0, "bleu_stderr": 0.0, "chrf": 0.007148103038872972, "chrf_stderr": 9.594096858911254e-05, "ter": 1.0, "ter_stderr": 0.0}}, "versions": {"wmt20-en-de": 0}}
\ No newline at end of file

tests/testdata/wmt20-en-iu-v0-greedy_until

-f5688199890a48f73f2cc04a2152e35190f0e0ddd40e629fa24ee39d423ea389
+f5688199890a48f73f2cc04a2152e35190f0e0ddd40e629fa24ee39d423ea389
\ No newline at end of file

tests/testdata/wmt20-en-iu-v0-res.json

-{"results": {"wmt20-en-iu": {"bleu": 0.0, "bleu_stderr": 0.0, "chrf": 0.00011803644548940443, "chrf_stderr": 2.175287038623409e-05, "ter": 1.0, "ter_stderr": 0.0}}, "versions": {"wmt20-en-iu": 0}}
+{"results": {"wmt20-en-iu": {"bleu": 0.0, "bleu_stderr": 0.0, "chrf": 0.00011803644548940443, "chrf_stderr": 2.175287038623409e-05, "ter": 1.0, "ter_stderr": 0.0}}, "versions": {"wmt20-en-iu": 0}}
\ No newline at end of file

tests/testdata/wmt20-en-ja-v0-greedy_until

-7fe61f5847a51e93e97c84b39f4420978727754e4b6cf636a27851c615857530
+7fe61f5847a51e93e97c84b39f4420978727754e4b6cf636a27851c615857530
\ No newline at end of file

tests/testdata/wmt20-en-ja-v0-res.json

-{"results": {"wmt20-en-ja": {"bleu": 0.0, "bleu_stderr": 0.0, "chrf": 4.1308658294778584e-05, "chrf_stderr": 2.0456539027807417e-05, "ter": 1.0, "ter_stderr": 0.0}}, "versions": {"wmt20-en-ja": 0}}
+{"results": {"wmt20-en-ja": {"bleu": 0.0, "bleu_stderr": 0.0, "chrf": 4.1308658294778584e-05, "chrf_stderr": 2.0456539027807417e-05, "ter": 1.0, "ter_stderr": 0.0}}, "versions": {"wmt20-en-ja": 0}}
\ No newline at end of file

tests/testdata/wmt20-en-ja-v1-greedy_until

-7fe61f5847a51e93e97c84b39f4420978727754e4b6cf636a27851c615857530
+7fe61f5847a51e93e97c84b39f4420978727754e4b6cf636a27851c615857530
\ No newline at end of file

tests/testdata/wmt20-en-ja-v1-res.json

-{"results": {"wmt20-en-ja": {"bleu": 0.0, "bleu_stderr": 0.0, "chrf": 4.1305928226819116e-05, "chrf_stderr": 2.0455354158878388e-05, "ter": 1.0, "ter_stderr": 0.0}}, "versions": {"wmt20-en-ja": 1}}
+{"results": {"wmt20-en-ja": {"bleu": 0.0, "bleu_stderr": 0.0, "chrf": 4.1305928226819116e-05, "chrf_stderr": 2.0455354158878388e-05, "ter": 1.0, "ter_stderr": 0.0}}, "versions": {"wmt20-en-ja": 1}}
\ No newline at end of file

tests/testdata/wmt20-en-km-v0-greedy_until

-eb5365c46f22ffec9a157991627d6e1fd1117fccffaedfc73619e93bafb5a408
+eb5365c46f22ffec9a157991627d6e1fd1117fccffaedfc73619e93bafb5a408
\ No newline at end of file

tests/testdata/wmt20-en-km-v0-res.json

-{"results": {"wmt20-en-km": {"bleu": 0.0, "bleu_stderr": 0.0, "chrf": 1.9008351315007364e-05, "chrf_stderr": 7.136657625458525e-06, "ter": 1.0, "ter_stderr": 0.0}}, "versions": {"wmt20-en-km": 0}}
+{"results": {"wmt20-en-km": {"bleu": 0.0, "bleu_stderr": 0.0, "chrf": 1.9008351315007364e-05, "chrf_stderr": 7.136657625458525e-06, "ter": 1.0, "ter_stderr": 0.0}}, "versions": {"wmt20-en-km": 0}}
\ No newline at end of file

tests/testdata/wmt20-en-pl-v0-greedy_until

-952f02575d4936d93c4d2808d86c4bf5f1f3a0901212acee6cbc1f9cbd30d39e
+952f02575d4936d93c4d2808d86c4bf5f1f3a0901212acee6cbc1f9cbd30d39e
\ No newline at end of file

tests/testdata/wmt20-en-pl-v0-res.json

-{"results": {"wmt20-en-pl": {"bleu": 0.0, "bleu_stderr": 0.0, "chrf": 0.009006977773147825, "chrf_stderr": 0.00023387733367766675, "ter": 1.0, "ter_stderr": 0.0}}, "versions": {"wmt20-en-pl": 0}}
+{"results": {"wmt20-en-pl": {"bleu": 0.0, "bleu_stderr": 0.0, "chrf": 0.009006977773147825, "chrf_stderr": 0.00023387733367766675, "ter": 1.0, "ter_stderr": 0.0}}, "versions": {"wmt20-en-pl": 0}}
\ No newline at end of file

tests/testdata/wmt20-en-ps-v0-greedy_until

-8411c2cb73114cbd0c6e0f17eab2625d486cc3a601105deb0ea1338a401df689
+8411c2cb73114cbd0c6e0f17eab2625d486cc3a601105deb0ea1338a401df689
\ No newline at end of file

tests/testdata/wmt20-en-ps-v0-res.json

-{"results": {"wmt20-en-ps": {"bleu": 0.0, "bleu_stderr": 0.0, "chrf": 2.1193813610582323e-06, "chrf_stderr": 2.113911466119111e-06, "ter": 1.0, "ter_stderr": 0.0}}, "versions": {"wmt20-en-ps": 0}}
+{"results": {"wmt20-en-ps": {"bleu": 0.0, "bleu_stderr": 0.0, "chrf": 2.1193813610582323e-06, "chrf_stderr": 2.113911466119111e-06, "ter": 1.0, "ter_stderr": 0.0}}, "versions": {"wmt20-en-ps": 0}}
\ No newline at end of file

tests/testdata/wmt20-en-ru-v0-greedy_until

-a1613831f69c1679a54670092af40ce76617b79d7cc837984803b0fc52bb8bde
+a1613831f69c1679a54670092af40ce76617b79d7cc837984803b0fc52bb8bde
\ No newline at end of file

tests/testdata/wmt20-en-ru-v0-res.json

-{"results": {"wmt20-en-ru": {"bleu": 0.0, "bleu_stderr": 0.0, "chrf": 0.0007327811114614671, "chrf_stderr": 4.43155903515048e-05, "ter": 1.0, "ter_stderr": 0.0}}, "versions": {"wmt20-en-ru": 0}}
+{"results": {"wmt20-en-ru": {"bleu": 0.0, "bleu_stderr": 0.0, "chrf": 0.0007327811114614671, "chrf_stderr": 4.43155903515048e-05, "ter": 1.0, "ter_stderr": 0.0}}, "versions": {"wmt20-en-ru": 0}}
\ No newline at end of file

tests/testdata/wmt20-en-ta-v0-greedy_until

-5fc556fa90bca7f1b1396e97e392eac8080b0ad53488358799b8fc0b21a94cb1
+5fc556fa90bca7f1b1396e97e392eac8080b0ad53488358799b8fc0b21a94cb1
\ No newline at end of file

tests/testdata/wmt20-en-ta-v0-res.json

-{"results": {"wmt20-en-ta": {"bleu": 0.0, "bleu_stderr": 0.0, "chrf": 0.0, "chrf_stderr": 0.0, "ter": 1.0, "ter_stderr": 0.0}}, "versions": {"wmt20-en-ta": 0}}
+{"results": {"wmt20-en-ta": {"bleu": 0.0, "bleu_stderr": 0.0, "chrf": 0.0, "chrf_stderr": 0.0, "ter": 1.0, "ter_stderr": 0.0}}, "versions": {"wmt20-en-ta": 0}}
\ No newline at end of file

tests/testdata/wmt20-en-zh-v0-greedy_until

-67f0333ddbcb07d7a9ac12919129a18fe4fea24e4826a11bbdde4fd5ed5ed83f
+67f0333ddbcb07d7a9ac12919129a18fe4fea24e4826a11bbdde4fd5ed5ed83f
\ No newline at end of file

tests/testdata/wmt20-en-zh-v0-res.json

-{"results": {"wmt20-en-zh": {"bleu": 0.0, "bleu_stderr": 0.0, "chrf": 0.00014170297316825535, "chrf_stderr": 6.590669847391838e-05, "ter": 1.0, "ter_stderr": 0.0}}, "versions": {"wmt20-en-zh": 0}}
+{"results": {"wmt20-en-zh": {"bleu": 0.0, "bleu_stderr": 0.0, "chrf": 0.00014170297316825535, "chrf_stderr": 6.590669847391838e-05, "ter": 1.0, "ter_stderr": 0.0}}, "versions": {"wmt20-en-zh": 0}}
\ No newline at end of file

tests/testdata/wmt20-en-zh-v1-greedy_until

-67f0333ddbcb07d7a9ac12919129a18fe4fea24e4826a11bbdde4fd5ed5ed83f
+67f0333ddbcb07d7a9ac12919129a18fe4fea24e4826a11bbdde4fd5ed5ed83f
\ No newline at end of file