ART: Make run-test temp dir consistent

We use the username as a directory component in run-test. Use the
same when driven through the Makefile.

Drop the username in run-test when TMP_DIR is set.

Test: m test-art-host-run-test
Test: art/test/run-test --host 001-HelloWorld
Change-Id: I060997ffbd80cd4da30dd6ac8d3954641de3292b
2 files changed