Update V8 to r5388 as required by WebKit r66666

Change-Id: Ib3c42e9b7226d22c65c7077c543fe31afe62a318
diff --git a/src/arm/builtins-arm.cc b/src/arm/builtins-arm.cc
index 224b75f..a902fc2 100644
--- a/src/arm/builtins-arm.cc
+++ b/src/arm/builtins-arm.cc
@@ -481,6 +481,13 @@
 }
 
 
+void Builtins::Generate_StringConstructCode(MacroAssembler* masm) {
+  // TODO(849): implement custom construct stub.
+  // Generate a copy of the generic stub for now.
+  Generate_JSConstructStubGeneric(masm);
+}
+
+
 void Builtins::Generate_JSConstructCall(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- r0     : number of arguments
@@ -505,10 +512,6 @@
   // r0: number of arguments
   // r1: called object
   __ bind(&non_function_call);
-  // CALL_NON_FUNCTION expects the non-function constructor as receiver
-  // (instead of the original receiver from the call site).  The receiver is
-  // stack element argc.
-  __ str(r1, MemOperand(sp, r0, LSL, kPointerSizeLog2));
   // Set expected number of arguments to zero (not changing r0).
   __ mov(r2, Operand(0));
   __ GetBuiltinEntry(r3, Builtins::CALL_NON_FUNCTION_AS_CONSTRUCTOR);