Update migrated HF dataset paths (#1332)

* Update arc_easy.yaml

* Update flan_cot.yaml

* update HF dataset path

* Update freeform.yaml

* Update flan_cot.yaml

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Co-authored-by: Lintang Sutawika <lintang@eleuther.ai>

lm_eval/tasks/arc/arc_easy.yaml

 group:
   - ai2_arc
 task: arc_easy
-dataset_path: ai2_arc
+dataset_path: allenai/ai2_arc
 dataset_name: ARC-Easy
 output_type: multiple_choice
 training_split: train

lm_eval/tasks/benchmarks/flan/flan_cot.yaml

 group: flan_cot
 task:
   - include: yaml_templates/cot_template_yaml
-    dataset_path: gsmk
-    dataset_name: boolq
+    dataset_path: gsm8k
     use_prompt: promptsource:*
     validation_split: validation
   - include: yaml_templates/cot_template_yaml

lm_eval/tasks/qasper/bool.yaml

 group: qasper
 task: qasper_bool
-dataset_path: qasper
+dataset_path: allenai/qasper
 output_type: multiple_choice
 training_split: train
 validation_split: validation

lm_eval/tasks/qasper/freeform.yaml

 group: qasper
 task: qasper_freeform
-dataset_path: qasper
+dataset_path: allenai/qasper
 output_type: generate_until
 training_split: train
 validation_split: validation