Fix nits on metrics_test

tests/lib/profiler/metrics_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.
 //
 
 import 'dart:profiler';
 import 'package:expect/expect.dart';
 
 testGauge1() {
   var gauge = new Gauge('test', 'alpha bravo', 0.0, 100.0);
@@ skipping 14 matching lines @@
 
 testGauge2() {
   var gauge = new Gauge('test', 'alpha bravo', 1.0, 2.0);
   Expect.equals(1.0, gauge.min);
   Expect.equals(2.0, gauge.max);
   Expect.equals(gauge.min, gauge.value);
   Expect.equals('test', gauge.name);
   Expect.equals('alpha bravo', gauge.description);
 
   Expect.throws(() {
-    // min > max.
+    // min argument > max argument .
     gauge = new Gauge('test', 'alpha bravo', 2.0, 1.0);
   });
 
   Expect.throws(() {
-    // min == max.
+    // min argument  == max argument .
     gauge = new Gauge('test', 'alpha bravo', 1.0, 1.0);
   });
 
   Expect.throws(() {
-    // min is null
+    // min argument is null
     gauge = new Gauge('test', 'alpha bravo', null, 1.0);
   });
 
   Expect.throws(() {
-    // min is not a double
+    // min argument is not a double
     gauge = new Gauge('test', 'alpha bravo', 'string', 1.0);
   });
 
   Expect.throws(() {
-    // max is null
+    // max argument is null
     gauge = new Gauge('test', 'alpha bravo', 1.0, null);
   });
 }
 
 testCounter() {
   var counter = new Counter('test', 'alpha bravo');
   Expect.equals(0.0, counter.value);
   Expect.equals('test', counter.name);
   Expect.equals('alpha bravo', counter.description);
   counter.value = 1.0;
@@ skipping 36 matching lines @@
 }
 
 main() {
   testGauge1();
   testGauge2();
   testCounter();
   testCustomCounter();
   testMetricNameCollision();
   testBadName();
 }