Fix test.dart's --build-directory option to accept absolute paths.

tools/testing/dart/test_suite.dart

Index: tools/testing/dart/test_suite.dart
diff --git a/tools/testing/dart/test_suite.dart b/tools/testing/dart/test_suite.dart
index 841c13a79add11cd43a3fb1ead077726918bf917..ad7e9f49663d6b11bbd603b1e9dc6f65dbe75382 100644
--- a/tools/testing/dart/test_suite.dart
+++ b/tools/testing/dart/test_suite.dart
@@ -1028,15 +1028,14 @@ class StandardTestSuite extends TestSuite {
     var minified = configuration['minified'] ? '-minified' : '';
     var dirName = "${configuration['compiler']}-${configuration['runtime']}"
                   "$checked$minified";
-    var generatedTestPath = Strings.join([
-        buildDir,
-        'generated_tests',
-        dirName,
-        testUniqueName
-    ], '/');
-
-    TestUtils.mkdirRecursive(new Path('.'), new Path(generatedTestPath));
-    return new File(generatedTestPath).fullPathSync().replaceAll('\\', '/');
+    Path generatedTestPath = new Path.fromNative(buildDir)

[ahe, 2012/12/03 11:42:39]

Nice.

+        .append('generated_tests')
+        .append(dirName)
+        .append(testUniqueName);
+
+    TestUtils.mkdirRecursive(new Path('.'), generatedTestPath);
+    return new File.fromPath(generatedTestPath).fullPathSync()
+        .replaceAll('\\', '/');
   }
 
   String get scriptType {