When an override_apex named Foo overrides an apex module named Bar, the
Make modules from Foo have Foo as their suffix. Previously the suffix
was Bar for both of the overriding and the overridden APEXes, causing
name conflicts in the Make side.
Bug: 144338929
Test: apex_test.go
Change-Id: I1396910ab294ba5f5e0585af6d37f1eab9460250