Check revoked_mark_stacks empty in FinishPhase()

Bug: 140119552
Test: art/test/testrunner/testrunner.py --target
Change-Id: I69c3d99cb49db57752f7bf680ece45703001605a
diff --git a/runtime/gc/collector/concurrent_copying.cc b/runtime/gc/collector/concurrent_copying.cc
index e3f5c33..01c032a 100644
--- a/runtime/gc/collector/concurrent_copying.cc
+++ b/runtime/gc/collector/concurrent_copying.cc
@@ -3628,6 +3628,7 @@
   Thread* const self = Thread::Current();
   {
     MutexLock mu(self, mark_stack_lock_);
+    CHECK(revoked_mark_stacks_.empty());
     CHECK_EQ(pooled_mark_stacks_.size(), kMarkStackPoolSize);
   }
   // kVerifyNoMissingCardMarks relies on the region space cards not being cleared to avoid false