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

src/s390/macro-assembler-s390.cc

Index: src/s390/macro-assembler-s390.cc
diff --git a/src/s390/macro-assembler-s390.cc b/src/s390/macro-assembler-s390.cc
index 51085b036b2491b3b381b85769a61bb8a9f414f4..09cbc02734b302d359ce0b99f97946e3556197cf 100644
--- a/src/s390/macro-assembler-s390.cc
+++ b/src/s390/macro-assembler-s390.cc
@@ -2526,7 +2526,9 @@ void MacroAssembler::CallRuntime(const Runtime::Function* f, int num_arguments,
   // arguments passed in because it is constant. At some point we
   // should remove this need and make the runtime routine entry code
   // smarter.
-  mov(r2, Operand(num_arguments));
+  if (num_arguments >= 0) {
+    mov(r2, Operand(num_arguments));
+  }
   mov(r3, Operand(ExternalReference(f, isolate())));
   CEntryStub stub(isolate(),
 #if V8_TARGET_ARCH_S390X