Add test for tokenization of 1e

dart/tests/try/paste_content_rewriting_test.dart

 // Copyright (c) 2014, 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.
 
 // SharedOptions=--package-root=sdk/lib/_internal/
 
 library trydart.paste_test;
 
 import 'dart:html';
 import 'dart:async';
@@ skipping 11 matching lines @@
 import '../../pkg/expect/lib/expect.dart';
 import '../../pkg/async_helper/lib/async_helper.dart';
 
 const Map<String, String> tests = const <String, String> {
   '<span><p>//...</p>}</span>': '//...\n}\n',
   'someText': 'someText\n',
   '"\$"': '"\$"<DIAGNOSTIC>\n',
   '"\$\$"': '"\$\$<DIAGNOSTIC>"<DIAGNOSTIC>\n',
   '"\$\$4"': '"\$\$<DIAGNOSTIC>4<DIAGNOSTIC>"\n',
   '"\$\$4 "': '"\$\$<DIAGNOSTIC>4<DIAGNOSTIC> "\n',
+  '1e': '1<DIAGNOSTIC>e\n',
 };
 
 List<Node> queryDiagnosticNodes() {
   return mainEditorPane.querySelectorAll('a.diagnostic>span');
 }
 
 Future runTests() {
   Iterator<String> keys = tests.keys.iterator;
   keys.moveNext();
   mainEditorPane.innerHtml = keys.current;
@@ skipping 27 matching lines @@
   var interaction = new InteractionManager();
   mainEditorPane = new DivElement();
   document.body.append(mainEditorPane);
   observer = new MutationObserver(interaction.onMutation)
       ..observe(mainEditorPane, childList: true, characterData: true, subtree: true);
 
   mainEditorPane.innerHtml = "<span><p>//...</p>}</span>";
 
   asyncTest(runTests);
 }