[heap] Do more incremental marking work in tasks.

test/cctest/heap/test-spaces.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 431 matching lines @@
 
   delete compaction_space;
   delete old_space;
 
   memory_allocator->TearDown();
   delete memory_allocator;
 }
 
 
 TEST(LargeObjectSpace) {
+  // This test does not initialize allocated objects, which confuses the
+  // incremental marker.
+  FLAG_incremental_marking = false;
   v8::V8::Initialize();
 
   LargeObjectSpace* lo = CcTest::heap()->lo_space();
   CHECK(lo != NULL);
 
   int lo_size = Page::kPageSize;
 
   Object* obj = lo->AllocateRaw(lo_size, NOT_EXECUTABLE).ToObjectChecked();
   CHECK(obj->IsHeapObject());
 
@@ skipping 325 matching lines @@
   HeapObject* filler =
       HeapObject::FromAddress(array->address() + array->Size());
   CHECK_EQ(filler->map(), CcTest::heap()->two_pointer_filler_map());
 
   const size_t shrinked = page->ShrinkToHighWaterMark();
   CHECK_EQ(0, shrinked);
 }
 
 }  // namespace internal
 }  // namespace v8