[wasm] Implement correct 2-level namespace for imports.

test/mjsunit/wasm/instantiate-module-basic.js

 // Copyright 2015 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");
 
 let kReturnValue = 117;
@@ skipping 102 matching lines @@
     assertTrue(instance_1 != instance_2);
   });
 })();
 
 (function InstancesAreIsolatedFromEachother() {
   print("InstancesAreIsolatedFromEachother...");
   var builder = new WasmModuleBuilder();
   builder.addMemory(1,1, true);
   var kSig_v_i = makeSig([kAstI32], []);
   var signature = builder.addType(kSig_v_i);
-  builder.addImport("some_value", kSig_i_v);
-  builder.addImport("writer", signature);
+  builder.addImport("m", "some_value", kSig_i_v);
+  builder.addImport("m", "writer", signature);
 
   builder.addFunction("main", kSig_i_i)
     .addBody([
       kExprGetLocal, 0,
       kExprI32LoadMem, 0, 0,
       kExprI32Const, 1,
       kExprCallIndirect, signature, kTableZero,
       kExprGetLocal,0,
       kExprI32LoadMem,0, 0,
       kExprCallFunction, 0,
@@ skipping 13 matching lines @@
   var mem_1 = new WebAssembly.Memory({initial: 1});
   var mem_2 = new WebAssembly.Memory({initial: 1});
   var view_1 = new Int32Array(mem_1.buffer);
   var view_2 = new Int32Array(mem_2.buffer);
 
   view_1[0] = 42;
   view_2[0] = 1000;
 
   var outval_1;
   var outval_2;
-  var i1 = new WebAssembly.Instance(module, {some_value: () => 1,
-                                    writer: (x)=>outval_1 = x }, mem_1);
-  var i2 = new WebAssembly.Instance(module, {some_value: () => 2,
-                                    writer: (x)=>outval_2 = x }, mem_2);
+  var i1 = new WebAssembly.Instance(module, {m: {some_value: () => 1,
+                                                 writer: (x)=>outval_1 = x }},
+                                    mem_1);
+  var i2 = new WebAssembly.Instance(module, {m: {some_value: () => 2,
+                                                 writer: (x)=>outval_2 = x }},
+                                    mem_2);
 
   assertEquals(43, i1.exports.main(0));
   assertEquals(1002, i2.exports.main(0));
 
   assertEquals(42, outval_1);
   assertEquals(1000, outval_2);
 })();
 
 (function GlobalsArePrivateToTheInstance() {
   print("GlobalsArePrivateToTheInstance...");
@@ skipping 45 matching lines @@
   assertEquals(1, i1.exports.f());
   assertEquals(1000, i2.exports.f());
 })();
 
 (function MustBeMemory() {
   print("MustBeMemory...");
   var memory = new ArrayBuffer(65536);
   var module = new WebAssembly.Module(buffer);
   assertThrows(() => new WebAssembly.Instance(module, null, memory), TypeError);
 })();