[wasm] Memory buffer should be detached after Memory.Grow

test/mjsunit/wasm/import-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
 
 load("test/mjsunit/wasm/wasm-constants.js");
 load("test/mjsunit/wasm/wasm-module-builder.js");
 
 (function TestOne() {
@@ skipping 379 matching lines @@
 
   // initial size is too large
   assertThrows(() => builder.instantiate({m: {m: new WebAssembly.Memory({initial: 3, maximum: 3})}}));
 
   // maximum size is too large
   assertThrows(() => builder.instantiate({m: {m: new WebAssembly.Memory({initial: 1, maximum: 4})}}));
 
   // no maximum
   assertThrows(() => builder.instantiate({m: {m: new WebAssembly.Memory({initial: 1})}}));
 })();
+
+(function TestMemoryGrowDetachBuffer() {
+  print("TestMemoryGrowDetachBuffer");
+  let memory = new WebAssembly.Memory({initial: 1, maximum: 5});
+  var builder = new WasmModuleBuilder();
+  builder.addImportedMemory("m", "imported_mem");
+  let instance = builder.instantiate({m: {imported_mem: memory}});
+  let buffer = memory.buffer;
+  assertEquals(kPageSize, buffer.byteLength);
+  assertEquals(1, memory.grow(2));
+  assertTrue(buffer !== memory.buffer);
+  assertEquals(0, buffer.byteLength);
+  assertEquals(3*kPageSize, memory.buffer.byteLength);
+})();