Add ReferenceQueue test

Also cleaned up reference queue.
TODO: Add tests for missing functionality.

Bug: 10808403

Change-Id: I182f9cb69022fe542ea9e53d4c6d35cff90af332
diff --git a/build/Android.gtest.mk b/build/Android.gtest.mk
index 340304a..1347849 100644
--- a/build/Android.gtest.mk
+++ b/build/Android.gtest.mk
@@ -102,6 +102,7 @@
   runtime/gc/accounting/card_table_test.cc \
   runtime/gc/accounting/space_bitmap_test.cc \
   runtime/gc/heap_test.cc \
+  runtime/gc/reference_queue_test.cc \
   runtime/gc/space/dlmalloc_space_base_test.cc \
   runtime/gc/space/dlmalloc_space_static_test.cc \
   runtime/gc/space/dlmalloc_space_random_test.cc \