[wasm] Exported memory should set maximum property when maximum is defined.

test/mjsunit/regress/wasm/regression-651961.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
 
 load("test/mjsunit/wasm/wasm-constants.js");
 load("test/mjsunit/wasm/wasm-module-builder.js");
 
 (function() {
   var builder = new WasmModuleBuilder();
-  builder.addMemory(1, 1, false);
+  builder.addMemory(1, 32, false);
   builder.addFunction("foo", kSig_i_v)
     .addBody([
               kExprMemorySize, kMemoryZero,
               kExprI32Const, 0x10,
               kExprGrowMemory, kMemoryZero,
               kExprI32Mul,
               ])
               .exportFunc();
   var module = builder.instantiate();
   var result = module.exports.foo();
   assertEquals(1, result);
 })();