[runtime] Add %ToString and %_ToString and remove the TO_STRING builtin.

src/mips/builtins-mips.cc

 // 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.
 
 #if V8_TARGET_ARCH_MIPS
 
 #include "src/codegen.h"
 #include "src/debug/debug.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 222 matching lines @@
   __ mov(argument, a0);
   __ IncrementCounter(counters->string_ctor_conversions(), 1, a3, t0);
   __ Branch(&argument_is_string);
 
   // Invoke the conversion builtin and put the result into a2.
   __ bind(&convert_argument);
   __ push(function);  // Preserve the function.
   __ IncrementCounter(counters->string_ctor_conversions(), 1, a3, t0);
   {
     FrameScope scope(masm, StackFrame::INTERNAL);
-    __ push(a0);
-    __ InvokeBuiltin(Context::TO_STRING_BUILTIN_INDEX, CALL_FUNCTION);
+    ToStringStub stub(masm->isolate());
+    __ CallStub(&stub);
   }
   __ pop(function);
   __ mov(argument, v0);
   __ Branch(&argument_is_string);
 
   // Load the empty string into a2, remove the receiver from the
   // stack, and jump back to the case where the argument is a string.
   __ bind(&no_arguments);
   __ LoadRoot(argument, Heap::kempty_stringRootIndex);
   __ Drop(1);
@@ skipping 1625 matching lines @@
   }
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS