Fix obsolete method change check.

We were incorrectly checking for changes in the obsolete-method map.
This could cause issues if a class was redefined multiple times.

Bug: 37475600

Test: ./test.py --host -j40
Test: cts-tradefed run cts-dev --module CtsJvmtiRedefineClassesHostTestCases

Change-Id: Icf39d5154c0e48461405b700bf1fa20830195fc1
(cherry picked from commit 70713df8e245ef0df597474b96ac33fcfb3d99ed)
8 files changed