[turbofan] Eliminate typed array bounds checks if both key and length are constant.

test/mjsunit/asm/int32array-constant-key.js

+// Copyright 2014 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.
+
+function Module(stdlib, foreign, heap) {
+  "use asm";
+  var MEM32 = new stdlib.Int32Array(heap);
+  function load0() {
+    return MEM32[0];
+  }
+  function load4() {
+    return MEM32[4];
+  }
+  function store0(v) {
+    MEM32[0] = v;
+  }
+  function store4(v) {
+    MEM32[4] = v;
+  }
+  return { load0: load0, store0: store0, load4: load4, store4: store4 };
+}
+
+var m = Module(this, {}, new ArrayBuffer(4));
+
+assertEquals(0, m.load0());
+assertEquals(undefined, m.load4());
+m.store0(0x12345678);
+assertEquals(0x12345678, m.load0());
+assertEquals(undefined, m.load4());
+m.store4(43);
+assertEquals(0x12345678, m.load0());
+assertEquals(undefined, m.load4());