trusty: tests: use GTEST_SKIP() where tests aren't supported am: 0daff94f84

Original change: https://android-review.googlesource.com/c/trusty/lk/trusty/+/2936719

Change-Id: I4a6e2b4c57e50d4e97381ea4a42a5f51a802590c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>