ART-tests: remove DX dependency from 672/673

In some test cases D8 inverts an IF condition compared to the code
generated by DX and the corresponding checks fail. This CL updates
the checks for D8 and enables it.

Test: art/test.py -b -r --host -t 672-checker-throw-method
Test: art/test.py -b -r --host -t 673-checker-throw-vmethod
Bug: 65168732
Change-Id: I8beeedfa662e35f918701fb59955b6f93bb47686