Use WaitHoldingLocks in ReferenceProcessor::MakeCircularListIfUnenqueued.

The caller may be holding mutator_lock_, so we must use WaitHoldingLocks.
Otherwise we get 'bad_mutexes_held' error with debug build.

See also https://android-review.googlesource.com/#/c/93892.

Change-Id: I87b1119e22a9934fdc622c4c4e2690b8b552b539
Signed-off-by: Pavel Vyssotski <pavel.n.vyssotski@intel.com>
Merge "Use WaitHoldingLocks in ReferenceProcessor::MakeCircularListIfUnenqueued."