Replace ObjectSet with LargeObjectBitmap.

Speeds up large object marking since large objects no longer required
a lock. Changed the GCs to use the heap bitmap for marking objects
which aren't in the fast path. This eliminates the need for a
MarkLargeObject function.

Maps before (10 GC iterations):
Mean partial time: 180ms
Mean sticky time: 151ms

Maps after:
Mean partial time: 161ms
Mean sticky time: 101ms

Note: the GC durations are long due to recent ergonomic changes and
because the fast bulk free hasn't yet been enabled. Over 50% of the
GC time is spent in RosAllocSpace::FreeList.

Bug: 13571028

Change-Id: Id8f94718aeaa13052672ccbae1e8edf77d653f62
diff --git a/runtime/mirror/object-inl.h b/runtime/mirror/object-inl.h
index 2505855..b195dea 100644
--- a/runtime/mirror/object-inl.h
+++ b/runtime/mirror/object-inl.h
@@ -51,14 +51,14 @@
       OFFSET_OF_OBJECT_MEMBER(Object, klass_), new_klass, false);
 }
 
-inline LockWord Object::GetLockWord(bool is_volatile) {
-  return LockWord(GetField32(OFFSET_OF_OBJECT_MEMBER(Object, monitor_), is_volatile));
+inline LockWord Object::GetLockWord(bool as_volatile) {
+  return LockWord(GetField32(OFFSET_OF_OBJECT_MEMBER(Object, monitor_), as_volatile));
 }
 
-inline void Object::SetLockWord(LockWord new_val, bool is_volatile) {
+inline void Object::SetLockWord(LockWord new_val, bool as_volatile) {
   // Force use of non-transactional mode and do not check.
   SetField32<false, false>(OFFSET_OF_OBJECT_MEMBER(Object, monitor_), new_val.GetValue(),
-                           is_volatile);
+                           as_volatile);
 }
 
 inline bool Object::CasLockWord(LockWord old_val, LockWord new_val) {