-Added all new test cases. Now test case for sort and stable sort are all teh same.
Similarly test cases for sort_by_key and stablesort_by_key test cases are also similar.
-Changed the test_common.h file to log only 8 test cases.
-Added new test cases to test offset for all the code paths.
-For sort_by_key routines calling the stable_sort_by_key routines.