Fixed bug which caused overwrite_cache to always be True (#19000)

* fixed bug which caused overwrite_cache to always be True (#18967).

* reformatting changes

examples/pytorch/language-modeling/run_clm_no_trainer.py

@@ -183,7 +183,7 @@ def parse_args():
         help="The number of processes to use for the preprocessing.",
     )
     parser.add_argument(
-        "--overwrite_cache", type=bool, default=False, help="Overwrite the cached training and evaluation sets"
+        "--overwrite_cache", action="store_true", help="Overwrite the cached training and evaluation sets"
     )
     parser.add_argument(
         "--no_keep_linebreaks", action="store_true", help="Do not keep line breaks when using TXT files."

examples/pytorch/language-modeling/run_mlm_no_trainer.py

@@ -190,7 +190,7 @@ def parse_args():
         help="The number of processes to use for the preprocessing.",
     )
     parser.add_argument(
-        "--overwrite_cache", type=bool, default=False, help="Overwrite the cached training and evaluation sets"
+        "--overwrite_cache", action="store_true", help="Overwrite the cached training and evaluation sets"
     )
     parser.add_argument(
         "--mlm_probability", type=float, default=0.15, help="Ratio of tokens to mask for masked language modeling loss"

examples/pytorch/question-answering/run_qa_beam_search_no_trainer.py

@@ -232,7 +232,7 @@ def parse_args():
         ),
     )
     parser.add_argument(
-        "--overwrite_cache", type=bool, default=False, help="Overwrite the cached training and evaluation sets"
+        "--overwrite_cache", action="store_true", help="Overwrite the cached training and evaluation sets"
     )
     parser.add_argument(
         "--max_predict_samples",

examples/pytorch/question-answering/run_qa_no_trainer.py

@@ -253,7 +253,7 @@ def parse_args():
         ),
     )
     parser.add_argument(
-        "--overwrite_cache", type=bool, default=False, help="Overwrite the cached training and evaluation sets"
+        "--overwrite_cache", action="store_true", help="Overwrite the cached training and evaluation sets"
     )
     parser.add_argument(
         "--max_predict_samples",

examples/pytorch/summarization/run_summarization_no_trainer.py

@@ -138,7 +138,7 @@ def parse_args():
         help="The number of processes to use for the preprocessing.",
     )
     parser.add_argument(
-        "--overwrite_cache", type=bool, default=None, help="Overwrite the cached training and evaluation sets"
+        "--overwrite_cache", action="store_true", help="Overwrite the cached training and evaluation sets"
     )
     parser.add_argument(
         "--max_target_length",

examples/pytorch/translation/run_translation_no_trainer.py

@@ -168,7 +168,7 @@ def parse_args():
         help="The number of processes to use for the preprocessing.",
     )
     parser.add_argument(
-        "--overwrite_cache", type=bool, default=None, help="Overwrite the cached training and evaluation sets"
+        "--overwrite_cache", action="store_true", help="Overwrite the cached training and evaluation sets"
     )
     parser.add_argument(
         "--max_length",