Optimizing: Fix weak method access check.

And improve generated code for accessing package private
methods from unresolved compiling class in the same package.

Test: Additional test in 727-checker-unresolved-class
Test: testrunner.py --host --optimizing --interpreter --jvm -t 727
Test: testrunner.py --host --optimizing
Bug: 161898207
Change-Id: Ia34552d90620e8e0398099522a5a52b4a45df15d
10 files changed