add an option to set the number of test images

Summary: Add an option to set the number of test images. Thus, during finetune, we can set a small number of test images (for only visualization purpose) to save the time for evaluation.

Reviewed By: leehomyc

Differential Revision: D28720086

fbshipit-source-id: 8085be6a0f4f8742784e3dafe255716f3ae02acb

d2go/data/gans.py

@@ -274,5 +274,5 @@ def inject_gan_datasets(cfg):
             real_json_path,
             real_folder,
             real_src_path,
-            max_num=5000,
+            max_num=cfg.D2GO_DATA.DATASETS.GAN_INJECTION.MAX_TEST_IMAGES,
         )