Merge "libutils: RefBase: extra check for double own" am: b0fe01da56

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2166103

Change-Id: Ie252e8a229d8151aad82347f6b216dbed752d86b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>