Revert^4 "Make class redefinition work with native methods on stack."

We had a problem where there was a brief period of time where the dex
file for an obsolete method could not be obtained. This meant that not
all functions of ArtMethod could safely be called, causing some
problems.

This reverts commit 38c20d4a.

Reason for revert: Fixed issues with interp-ac and relocate-npatchoat

Test: ART_TEST_RUN_TEST_RELOCATE_NO_PATCHOAT=true \
      ART_TEST_INTERPRETER_ACCESS_CHECKS=true \
      mma -j40 test-art-host

Change-Id: I04991f3e76813831b6446f97636b6fa404397f36