Improve heap lock annotations.

Fix a deadlock in non-concurrent mark sweep caught by this.
Broaden heap_bitmap_lock_ over bitmap swapping.

Change-Id: I5e749f25d181217d530e2f573dc8aee2685108ad
diff --git a/src/gc/heap_bitmap.h b/src/gc/heap_bitmap.h
index 23dcd47..1610df8 100644
--- a/src/gc/heap_bitmap.h
+++ b/src/gc/heap_bitmap.h
@@ -25,8 +25,7 @@
 
   class HeapBitmap {
    public:
-    bool Test(const Object* obj)
-        SHARED_LOCKS_REQUIRED(Locks::heap_bitmap_lock_) {
+    bool Test(const Object* obj) SHARED_LOCKS_REQUIRED(Locks::heap_bitmap_lock_) {
       SpaceBitmap* bitmap = GetSpaceBitmap(obj);
       if (LIKELY(bitmap != NULL)) {
         return bitmap->Test(obj);