Refactor module builder

test/mjsunit/wasm/import-table.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");
 
 function testCallImport(func, check) {
   var builder = new WasmModuleBuilder();
 
-  var sig_index = builder.addSignature(kSig_i_dd);
+  var sig_index = builder.addType(kSig_i_dd);
   builder.addImport("func", sig_index);
   builder.addFunction("main", sig_index)
     .addBody([
       kExprGetLocal, 0,            // --
       kExprGetLocal, 1,            // --
       kExprCallImport, 2, 0])      // --
     .exportAs("main");
 
   var main = builder.instantiate({func: func}).exports.main;
 
@@ skipping 250 matching lines @@
       kExprCallImport, kArity0, 1, // --
       kExprI32Add,                 // --
     ])                             // --
     .exportFunc();
 
   var main = builder.instantiate({foo: foo, bar: bar}).exports.main;
   assertEquals(expected, main());
 }
 
 testCallImport2(function() { return 33; }, function () { return 44; }, 77);