Fix live bytes counter in large object space after right trimming.

test/cctest/heap/test-heap.cc

Index: test/cctest/heap/test-heap.cc
diff --git a/test/cctest/heap/test-heap.cc b/test/cctest/heap/test-heap.cc
index 030ef5c6160a3121662e43376eb583f1b372292b..14c91153c766f35b24fac0b4f54355915c0c788c 100644
--- a/test/cctest/heap/test-heap.cc
+++ b/test/cctest/heap/test-heap.cc
@@ -6743,5 +6743,18 @@ TEST(Regress598319) {
   }
 }
 
+TEST(Regress609761) {
+  CcTest::InitializeVM();
+  v8::HandleScope scope(CcTest::isolate());
+  Heap* heap = CcTest::heap();
+  Isolate* isolate = heap->isolate();
+
+  intptr_t size_before = heap->SizeOfObjects();
+  Handle<FixedArray> array = isolate->factory()->NewFixedArray(200000);
+  array->Shrink(1);
+  intptr_t size_after = heap->SizeOfObjects();
+  CHECK_EQ(size_after, size_before + array->Size());
+}
+
 }  // namespace internal
 }  // namespace v8