Remove corelib/corelib_strong and migrate last two remaining tests.

pkg/dev_compiler/test/codegen_test.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.
 
 /// Tests code generation.
 ///
 /// Runs Dart Dev Compiler on all input in the `codegen` directory and checks
 /// that the output is what we expected.
 library dev_compiler.test.codegen_test;
 
@@ skipping 69 matching lines @@
 
   var summaryPaths = new Directory(path.join(codegenOutputDir, 'pkg'))
       .listSync()
       .map((e) => e.path)
       .where((p) => p.endsWith('.sum'))
       .toList();
 
   var sharedCompiler = new ModuleCompiler(new AnalyzerOptions.basic(
       dartSdkSummaryPath: sdkSummaryFile, summaryPaths: summaryPaths));
 
-  var testDirs = ['language', 'corelib', 'lib'];
+  var testDirs = ['language', 'corelib_2', 'lib'];
 
   // Copy all of the test files and expanded multitest files to
   // gen/codegen_tests. We'll compile from there.
   TestUtils.setDartDirUri(Platform.script.resolve('../../..'));
   var testFiles = _setUpTests(testDirs);
   _writeRuntimeStatus(testFiles);
 
   // Our default compiler options. Individual tests can override these.
   var defaultOptions = ['--no-source-map', '--no-summarize'];
   var compileArgParser = new ArgParser();
@@ skipping 352 matching lines @@
   StringLiteral uriLiteral = directive.uri;
   String uriContent = uriLiteral.stringValue;
   if (uriContent != null) {
     uriContent = uriContent.trim();
     directive.uriContent = uriContent;
   }
   return (directive as UriBasedDirectiveImpl).validate() == null
       ? uriContent
       : null;
 }