[wasm] Mask shift counts on architectures that don't implicitly mask.

test/mjsunit/wasm/asm-wasm-u32.js

 // Copyright 2016 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.
 
 // Flags: --expose-wasm
 
 function WrapInAsmModule(func) {
   function MODULE_NAME(stdlib) {
     "use asm";
     var imul = stdlib.Math.imul;
@@ skipping 179 matching lines @@
 var funcs = [
 // TODO(bradnelson):  u32_add,
 // TODO(bradnelson): u32_sub,
 // TODO(titzer): u32_mul requires Math.imul
 // TODO(titzer): u32_div by zero is incorrect
 // TODO(titzer): u32_mod by zero is incorrect
 // TODO(titzer): u32_mul crashes turbofan in asm.js mode
   u32_and,
   u32_or,
   u32_xor,
-// TODO(titzer): u32_shl on arm
-// TODO(titzer): u32_shr on arm
-// TODO(titzer): u32_sar on arm
+  u32_shl,
+  u32_shr,
+  u32_sar,
   u32_eq,
   u32_ne,
   u32_lt,
   u32_lteq,
   u32_gt,
   u32_gteq,
   // TODO(titzer): u32_min
   // TODO(titzer): u32_max
   // TODO(titzer): u32_abs
 ];
 
 (function () {
   for (func of funcs) {
     RunThreeWayTest(WrapInAsmModule(func), function (module) {
       for (a of inputs) {
         for (b of inputs) {
           var expected = func(a, b);
           assertEquals(expected, module.main(a, b));
         }
       }
     });
   }
 
 })();