Use ART gtests from the Testing Runtime APEX in ART device testing.

When running ART gtests on device (from the chroot environment), use
ART gtests contained in the (Testing) Runtime APEX instead of the
legacy ART gtests installed in /data/nativetest(64).

Also refactor and simplify the script used to run those tests on
device (tools/run-gtests.sh).

Test: ART chroot-based device testing
Bug: 129534335
Change-Id: I0883c7d2e716d7573ea4d27aba2ae133ec85753c
1 file changed