Revert "dx: Support v53 class files built from language level 8 sources."

Reason for revert: Broke dx tests that asserted that v53 class files cannot be parsed. Will resubmit the original CL once I've updated the tests.

This reverts commit ea1fbbc3c325dc42369cbe5002a039d6fbb43ebb.

Change-Id: I705bfbcf19fefbdb7e00b3b8baa86e29aee2222f
2 files changed