Stop defaulting to all tests builtin for coverage builds am: b53244352d

Original change: https://android-review.googlesource.com/c/trusty/lk/trusty/+/2755488

Change-Id: Id70abedfe12dd3fd89c65ca05afa5d7a268ffea4
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>