Remove deprecated 'str' getter on Match.

tests/corelib/string_pattern_test.dart

 // Copyright (c) 2011, 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.
 // Dart test for testing String.allMatches.
 
 import "package:expect/expect.dart";
 
 String str = "this is a string with hello here and hello there";
 
 main() {
@@ skipping 16 matching lines @@
 testOneMatch() {
   String helloPattern = "with hello";
   Iterable<Match> matches = helloPattern.allMatches(str);
   var iterator = matches.iterator;
   Expect.isTrue(iterator.moveNext());
   Match match = iterator.current;
   Expect.isFalse(iterator.moveNext());
   Expect.equals(str.indexOf('with', 0), match.start);
   Expect.equals(str.indexOf('with', 0) + helloPattern.length, match.end);
   Expect.equals(helloPattern, match.pattern);
-  Expect.equals(str, match.str);
+  Expect.equals(str, match.input);
   Expect.equals(helloPattern, match[0]);
   Expect.equals(0, match.groupCount);
 }
 
 testTwoMatches() {
   String helloPattern = "hello";
   Iterable<Match> matches = helloPattern.allMatches(str);
 
   int count = 0;
   int start = 0;
   for (var match in matches) {
     count++;
     Expect.equals(str.indexOf('hello', start), match.start);
     Expect.equals(
         str.indexOf('hello', start) + helloPattern.length, match.end);
     Expect.equals(helloPattern, match.pattern);
-    Expect.equals(str, match.str);
+    Expect.equals(str, match.input);
     Expect.equals(helloPattern, match[0]);
     Expect.equals(0, match.groupCount);
     start = match.end;
   }
   Expect.equals(2, count);
 }
 
 testEmptyPattern() {
   String pattern = "";
   Iterable<Match> matches = pattern.allMatches(str);
@@ skipping 25 matching lines @@
   Expect.isNull(pattern.matchAsPrefix(str, 2));
   m = pattern.matchAsPrefix(str, 3);
   Expect.equals("an", m[0]);
   Expect.equals(3, m.start);
   Expect.isNull(pattern.matchAsPrefix(str, 4));
   Expect.isNull(pattern.matchAsPrefix(str, 5));
   Expect.isNull(pattern.matchAsPrefix(str, 6));
   Expect.throws(() => pattern.matchAsPrefix(str, -1));
   Expect.throws(() => pattern.matchAsPrefix(str, 7));
 }