[builtins] Start refactoring the Apply builtin.

src/arm/macro-assembler-arm.cc

Index: src/arm/macro-assembler-arm.cc
diff --git a/src/arm/macro-assembler-arm.cc b/src/arm/macro-assembler-arm.cc
index 212a9f2dcde267d615511616bd1af2836d695b97..4f6b730638d4f0234772a1889450c7a659d4db20 100644
--- a/src/arm/macro-assembler-arm.cc
+++ b/src/arm/macro-assembler-arm.cc
@@ -2795,6 +2795,17 @@ void MacroAssembler::AssertSmi(Register object) {
   }
 }
 
+void MacroAssembler::AssertFixedArray(Register object) {
+  if (emit_debug_code()) {
+    STATIC_ASSERT(kSmiTag == 0);
+    tst(object, Operand(kSmiTagMask));
+    Check(ne, kOperandIsASmiAndNotAFixedArray);
+    push(object);
+    CompareObjectType(object, object, object, FIXED_ARRAY_TYPE);
+    pop(object);
+    Check(eq, kOperandIsNotAFixedArray);
+  }
+}
 
 void MacroAssembler::AssertFunction(Register object) {
   if (emit_debug_code()) {