[wasm] Names of exported functions should be the stringified function index.

test/mjsunit/wasm/export-table.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 testExportedMain() {
@@ skipping 80 matching lines @@
   } catch (e) {
     assertContains("Duplicate export", e.toString());
   }
 })();
 
 
 (function testExportMultipleIdentity() {
   print("TestExportMultipleIdentity...");
   var builder = new WasmModuleBuilder();
 
-  builder.addFunction("one", kSig_v_v).addBody([kExprNop])
+  var f = builder.addFunction("one", kSig_v_v).addBody([kExprNop])
     .exportAs("a")
     .exportAs("b")
     .exportAs("c");
 
   let instance = builder.instantiate();
   let e = instance.exports;
   assertEquals("function", typeof e.a);
   assertEquals("function", typeof e.b);
   assertEquals("function", typeof e.c);
   assertSame(e.a, e.b);
   assertSame(e.a, e.c);
-  assertEquals("a", e.a.name);
+  assertEquals(String(f.index), e.a.name);
 })();