Fix "holding ThreadListLock while doing condition variable wait on HeapLock"

Now we release the ThreadListLock if we are going to wait on the heap condition variable in WaitForConcurrentGC.

Change-Id: I506c8ff93f4b79ee74c98b7936a7d155be833b90
diff --git a/build/Android.common.mk b/build/Android.common.mk
index 72ab76e..6640430 100644
--- a/build/Android.common.mk
+++ b/build/Android.common.mk
@@ -211,6 +211,7 @@
 	src/runtime.cc \
 	src/runtime_support.cc \
 	src/scoped_thread_list_lock.cc \
+	src/scoped_thread_list_lock_releaser.cc \
 	src/signal_catcher.cc \
 	src/space.cc \
 	src/stack.cc \