libbufferhubqueue: sanitize logs and Android.bp

1/ Use ALOGD_IF(TRACE, "xxx") and proper clags to enable/display verbose
debugging message.
2/ Make sure that tests targets are visible to Soong.

Bug: 36446316
Test: Built and ran libbufferhubqueue_test, no more spam.
Change-Id: I1b7fc5410dc0c07d8edb6d9cf788e6e5f97afd14
5 files changed