Temporarily exclude `JniCompilerTests` from the ART MTS definition. am: f53fa282cc am: 39091af211

Original change: https://android-review.googlesource.com/c/platform/art/+/2218043

Change-Id: Ie84c4f9fd0ae1c459d778ee40cca0d564cff589b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>