[heap] Add CHECK for non-null object to LeftTrimFixedArray

R=cbruni@chromium.org

Review-Url: https://codereview.chromium.org/2098483002
Cr-Commit-Position: refs/heads/master@{#37216}

src/heap/heap.cc

@@ -3154,6 +3154,7 @@ void Heap::AdjustLiveBytes(HeapObject* object, int by, InvocationMode mode) {
 
 FixedArrayBase* Heap::LeftTrimFixedArray(FixedArrayBase* object,
                                          int elements_to_trim) {
+  CHECK_NOT_NULL(object);
   DCHECK(!object->IsFixedTypedArrayBase());
   DCHECK(!object->IsByteArray());
   const int element_size = object->IsFixedArray() ? kPointerSize : kDoubleSize;