[wasm] Support validation of asm.js modules with != 3 args.

src/x64/macro-assembler-x64.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_X64
 
 #include "src/base/bits.h"
 #include "src/base/division-by-constant.h"
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
@@ skipping 685 matching lines @@
                                  SaveFPRegsMode save_doubles) {
   // If the expected number of arguments of the runtime function is
   // constant, we check that the actual number of arguments match the
   // expectation.
   CHECK(f->nargs < 0 || f->nargs == num_arguments);
 
   // TODO(1236192): Most runtime routines don't need the number of
   // arguments passed in because it is constant. At some point we
   // should remove this need and make the runtime routine entry code
   // smarter.
-  Set(rax, num_arguments);
+  if (num_arguments >= 0) {
+    Set(rax, num_arguments);
+  }
   LoadAddress(rbx, ExternalReference(f, isolate()));
   CEntryStub ces(isolate(), f->result_size, save_doubles);
   CallStub(&ces);
 }
 
 
 void MacroAssembler::CallExternalReference(const ExternalReference& ext,
                                            int num_arguments) {
   Set(rax, num_arguments);
   LoadAddress(rbx, ext);
@@ skipping 5098 matching lines @@
   movl(rax, dividend);
   shrl(rax, Immediate(31));
   addl(rdx, rax);
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64