Use worst-fit allocation in old space for prentured objects.

src/mark-compact.cc

Index: src/mark-compact.cc
diff --git a/src/mark-compact.cc b/src/mark-compact.cc
index 63263ba131c289132d37ddb2fca05b0c6c889cb3..d2511e7cd1682dc331f8eee5655ea8de0f740abc 100644
--- a/src/mark-compact.cc
+++ b/src/mark-compact.cc
@@ -2676,7 +2676,8 @@ bool MarkCompactCollector::TryPromoteObject(HeapObject* object,
 
     ASSERT(target_space == heap()->old_pointer_space() ||
            target_space == heap()->old_data_space());
-    MaybeObject* maybe_result = target_space->AllocateRaw(object_size);
+    MaybeObject* maybe_result =
+        target_space->AllocateRaw<FreeList::BEST_FIT>(object_size);
     if (maybe_result->ToObject(&result)) {
       HeapObject* target = HeapObject::cast(result);
       MigrateObject(target->address(),
@@ -2799,7 +2800,7 @@ void MarkCompactCollector::EvacuateLiveObjectsFromPage(Page* p) {
 
       int size = object->Size();
 
-      MaybeObject* target = space->AllocateRaw(size);
+      MaybeObject* target = space->AllocateRaw<FreeList::BEST_FIT>(size);
       if (target->IsFailure()) {
         // OS refused to give us memory.
         V8::FatalProcessOutOfMemory("Evacuation");