Fix running zipapex tests with arbitrary cwd.

When running continuously the cwd is not always ANDROID_BUILD_TOP.
This could cause issues if OUT_DIR is relative to ANDROID_BUILD_TOP
for art-linux-bionic-x64-zipapex tests.

Test: ./test/testrunner/run_build_test_target.py art-linux-bionic-x64-zipapex
Change-Id: I452cd70ec317257bf235532381a5784e9ebf253b
1 file changed