Refactor apex build rule and add test apex

This is used to setup installation test.

Bug: 146416755
Test: atest CronetApiTest
Change-Id: Ib4b3a559f1cab1c68c35ee79fab1f2590ea12de7
Merged-In: Ib4b3a559f1cab1c68c35ee79fab1f2590ea12de7
3 files changed