Support multi-ABI in tests.

Build the test .so for all ABIs and then pick the right one to load at
runtime. (The executable doesn't need this, since it runs in its own
process.)

Bug: 123281572
Test: atest DexLoggerIntegrationTests
Test: atest DexLoggerIntegrationTests -- --abi armeabi-v7a
Change-Id: I0696ef75e42834b13524abde619dc0f8e79c8363
2 files changed