Marking bluetooth_test_gd as not unit tests

There are few stability issue right now with some of the tests that can result in flakiness.
Example b/176832968 b/176170066 those will need to be addressed first.

Change-Id: Iadcce2e7aafb7df22bcca527ee2bec6f8a08d385
Test: presubmit
Bug: 176832968