Strong mode cleaning of many dart2js tests.

tests/compiler/dart2js/memory_compiler.dart

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dart2js.test.memory_compiler;
 
 import 'dart:async';
 
 import 'package:compiler/compiler.dart' show DiagnosticHandler;
 import 'package:compiler/compiler_new.dart'
@@ skipping 155 matching lines @@
           packageRoot: packageRoot,
           options: options,
           environment: {},
           packageConfig: packageConfig,
           packagesDiscoveryProvider: packagesDiscoveryProvider));
 
   if (cachedCompiler != null) {
     Types types = cachedCompiler.types;
     compiler.types = types.copy(compiler.resolution);
     Map copiedLibraries = {};
-    cachedCompiler.libraryLoader.libraries.forEach((library) {
+    cachedCompiler.libraryLoader.libraries.forEach((dynamic library) {
       if (library.isPlatformLibrary) {
-        var libraryLoader = compiler.libraryLoader;
+        dynamic libraryLoader = compiler.libraryLoader;
         libraryLoader.mapLibrary(library);
         copiedLibraries[library.canonicalUri] = library;
       }
     });
     compiler.processLoadedLibraries(new MemoryLoadedLibraries(copiedLibraries));
     ResolutionEnqueuer resolutionEnqueuer = compiler.startResolution();
 
     compiler.backend.constantCompilerTask
         .copyConstantValues(cachedCompiler.backend.constantCompilerTask);
 
@@ skipping 61 matching lines @@
       handler = (Uri uri, int begin, int end, String message, Diagnostic kind) {
         diagnosticHandler(uri, begin, end, message, kind);
         formattingHandler(uri, begin, end, message, kind);
       };
     }
   } else if (diagnosticHandler == null) {
     handler = (Uri uri, int begin, int end, String message, Diagnostic kind) {};
   }
   return handler;
 }