[Examples] Fixes inconsistency around eval vs val and predict vs test (#11380)
* added changes for uniformity
* modified files
* corrected typo
* fixed qa scripts
* fix typos
* fixed predict typo in qa no trainer
* fixed test file
* reverted trainer changes
* reverted trainer changes in custom exmaples
* updated readme
* added changes in deepspeed test
* added changes for predict and eval