Revert "Ensure that run-test preserves exit status"

Fails:
test-art-host-run-test-debug-no-prebuild-interp-ac-no-relocate-ntrace-cms-checkjni-picimage-npictest-ndebuggable-no-jvmti-cdex-fast-134-nodex2oat-nofallback32 


This reverts commit 1fbd5309.

Change-Id: I29809f7bb26e4a9d81634bcf24d9ce151a41a583