Run-tests: Remove buildfailures.json

Since the per-test script is a method now,
we can easily exclude tests by just returning.

This has the side effect that directory with sources
is still created rather then being completely omitted.
But since the test will not be run, that is harmless.

Test: The (used) build artifacts are identical.
Change-Id: Ice728d654950dc6b47972306ed6ef9de337af833
26 files changed