[wasm] WebAssembly.Memory.grow() should handle the no instance case

test/mjsunit/wasm/memory.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
 
 // Basic tests.
 
 var outOfUint32RangeValue = 1e12;
 
@@ skipping 73 matching lines @@
   assertTrue(hasPropertyWasCalled);
 })();
 
 (function TestBuffer() {
   let memory = new WebAssembly.Memory({initial: 1});
   assertTrue(memory.buffer instanceof Object);
   assertTrue(memory.buffer instanceof ArrayBuffer);
   assertThrows(() => {'use strict'; memory.buffer = memory.buffer}, TypeError)
   assertThrows(() => ({__proto__: memory}).buffer, TypeError)
 })();
+
+(function TestMemoryGrow() {
+  var kPageSize = 65536;
+  let memory = new WebAssembly.Memory({initial: 1, maximum:30});
+  assertEquals(1, memory.grow(9));
+  assertTrue(memory.buffer instanceof ArrayBuffer);
+  assertTrue(10*kPageSize == memory.buffer.byteLength);
+  assertMemoryIsValid(memory);
+  assertThrows(() => memory.grow(21));
+})();