Reapply "Refactor constant part." (r4958) with fixes.

frog/tests/leg/src/PrettyParameterTest.dart

Index: frog/tests/leg/src/PrettyParameterTest.dart
diff --git a/frog/tests/leg/src/PrettyParameterTest.dart b/frog/tests/leg/src/PrettyParameterTest.dart
index f828a0e50c788b34d94ea37c45654900565f50ec..c7c967d96af56e267c8080f37e64318b555b4c17 100644
--- a/frog/tests/leg/src/PrettyParameterTest.dart
+++ b/frog/tests/leg/src/PrettyParameterTest.dart
@@ -75,7 +75,6 @@ main() {
 
   generated = compile(BAR, 'bar');
   regexp = const RegExp(@"function\(eval\$, \$\$eval\) {");
-  print(generated);
   Expect.isTrue(regexp.hasMatch(generated));
 
   generated = compile(PARAMETER_AND_TEMP, 'bar');
@@ -88,18 +87,18 @@ main() {
   generated = compile(NO_LOCAL, 'foo');
   regexp = const RegExp("return baz");
   Expect.isTrue(regexp.hasMatch(generated));
-  regexp = const RegExp("baz = 2");
+  regexp = const RegExp(@"baz = \(2\)");
   Expect.isTrue(regexp.hasMatch(generated));
-  regexp = const RegExp("baz = 3");
+  regexp = const RegExp(@"baz = \(3\)");
   Expect.isTrue(regexp.hasMatch(generated));
   regexp = const RegExp("bar === true");
   Expect.isTrue(regexp.hasMatch(generated));
 
   generated = compile(MULTIPLE_PHIS_ONE_LOCAL, 'foo');
-  regexp = const RegExp("var a = 2;");
+  regexp = const RegExp(@"var a = \(2\);");
   Expect.isTrue(regexp.hasMatch(generated));
 
-  regexp = const RegExp("a = 2;");
+  regexp = const RegExp(@"a = \(2\);");
   Iterator matches = regexp.allMatches(generated).iterator();
   Expect.isTrue(matches.hasNext());
   matches.next();