Fix type mismatch errors. Environments do not only contain strings.

tools/testing/dart/status_expression.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.
 
 #library("status_expression");
 
 /**
  * Parse and evaluate expressions in a .status file for Dart and V8.
  * There are set expressions and Boolean expressions in a .status file.
  * The grammar is:
@@ skipping 74 matching lines @@
       left.termValue(environment) == right.termValue(environment);
   String toString() => "(\$${left.name} == ${right.value})";
 }
 
 
 class TermVariable {
   String name;
 
   TermVariable(this.name);
 
-  String termValue(environment) => environment[name];
+  termValue(environment) => environment[name];

[Bill Hesse, 2011/11/11 09:43:19]

How about String termValue(environment) => environment[name].toString().  We
never want a boolean returned from this function, because it will be compared to
a string.

[Mads Ager (google), 2011/11/11 09:46:30]

Sounds good to me. I'll do that as part of my next changelist. Thanks. 

 }
 
 
 class TermConstant {
   String value;
 
   TermConstant(String this.value);
 
   String termValue(environment) => value;
 }
@@ skipping 183 matching lines @@
           "Expected identifier in expression, got ${scanner.current}");
       TermConstant right = new TermConstant(scanner.current);
       scanner.advance();
       return new Comparison(left, right);
     } else {
       return new BooleanVariable(left);
     } 
   }
 }