X87: [builtins] One runtime fallback is enough for the String constructor.

src/x87/macro-assembler-x87.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_X87_MACRO_ASSEMBLER_X87_H_
 #define V8_X87_MACRO_ASSEMBLER_X87_H_
 
 #include "src/assembler.h"
 #include "src/bailout-reason.h"
 #include "src/frames.h"
@@ skipping 786 matching lines @@
   // from the stack, clobbering only the esp register.
   void Drop(int element_count);
 
   void Call(Label* target) { call(target); }
   void Call(Handle<Code> target, RelocInfo::Mode rmode) { call(target, rmode); }
   void Jump(Handle<Code> target, RelocInfo::Mode rmode) { jmp(target, rmode); }
   void Push(Register src) { push(src); }
   void Push(const Operand& src) { push(src); }
   void Push(Immediate value) { push(value); }
   void Pop(Register dst) { pop(dst); }
+  void Pop(const Operand& dst) { pop(dst); }
   void PushReturnAddressFrom(Register src) { push(src); }
   void PopReturnAddressTo(Register dst) { pop(dst); }
 
   void Lzcnt(Register dst, Register src) { Lzcnt(dst, Operand(src)); }
   void Lzcnt(Register dst, const Operand& src);
 
   void Tzcnt(Register dst, Register src) { Tzcnt(dst, Operand(src)); }
   void Tzcnt(Register dst, const Operand& src);
 
   void Popcnt(Register dst, Register src) { Popcnt(dst, Operand(src)); }
@@ skipping 269 matching lines @@
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_X87_MACRO_ASSEMBLER_X87_H_