A64: Fix ArrayConstructorStub and remove GCC 4.8 specific flags.

src/a64/code-stubs-a64.cc

Index: src/a64/code-stubs-a64.cc
diff --git a/src/a64/code-stubs-a64.cc b/src/a64/code-stubs-a64.cc
index f77700dac229a79f1d483a8a914c0e2deb86f545..269b97f41c17fe8d4107bceb1fbaf832977aabeb 100644
--- a/src/a64/code-stubs-a64.cc
+++ b/src/a64/code-stubs-a64.cc
@@ -5429,10 +5429,10 @@ void ArrayConstructorStub::Generate(MacroAssembler* masm) {
 
     // In feedback_vector, we expect either undefined or a valid fixed array.
     Label okay_here;
-    Handle<Map> cell_map = masm->isolate()->factory()->cell_map();
+    Handle<Map> fixed_array_map = masm->isolate()->factory()->fixed_array_map();
     __ JumpIfRoot(feedback_vector, Heap::kUndefinedValueRootIndex, &okay_here);
-    __ Ldr(x10, FieldMemOperand(feedback_vector, Cell::kMapOffset));
-    __ Cmp(x10, Operand(cell_map));
+    __ Ldr(x10, FieldMemOperand(feedback_vector, FixedArray::kMapOffset));
+    __ Cmp(x10, Operand(fixed_array_map));
     __ Assert(eq, kExpectedFixedArrayInFeedbackVector);
 
     // slot_index should be a smi if we don't have undefined in feedback_vector.