Revert^4 "ART: Use proxy ArtMethod's data_ to store the interface method."

Fix a DCHECK() failure while visiting references for non-CC
moving GC by avoiding the DCHECK(); reference equality may
give false negatives at that stage as we may compare the new
reference against an old one for the same object.

Test: m test-art-host-gtest
Test: testrunner.py --host
Test: testrunner.py --host --jit
Test: testrunner.py --host --gcstress
Test: ART_DEFAULT_GC_TYPE=SS ART_USE_READ_BARRIER=false \
      testrunner.py --host --gcstress -t 048-reflect-v8

This reverts commit 76ccd09c3d98317dfbd179c6f5c231dcfc5d6996.

Change-Id: I13cc339d5b31fceedf39ea9a77f27369ba72279f
6 files changed