[turbofan] Introduce JSCallForwardVarargs operator.

src/ia32/code-stubs-ia32.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_IA32
 
 #include "src/code-stubs.h"
 #include "src/api-arguments.h"
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
@@ skipping 3674 matching lines @@
   __ pop(edi);   // Pop saved function.
   __ pop(eax);   // Remove saved parameter count.
   __ pop(eax);   // Pop return address.
   __ push(edi);  // Push function.
   __ push(edx);  // Push parameters pointer.
   __ push(ecx);  // Push parameter count.
   __ push(eax);  // Push return address.
   __ TailCallRuntime(Runtime::kNewSloppyArguments);
 }
 
-
 void FastNewStrictArgumentsStub::Generate(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- edi    : function
   //  -- esi    : context
   //  -- ebp    : frame pointer
   //  -- esp[0] : return address
   // -----------------------------------
   __ AssertFunction(edi);
 
   // Make edx point to the JavaScript frame.
@@ skipping 496 matching lines @@
                            kStackUnwindSpace, nullptr, return_value_operand,
                            NULL);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_IA32