Fixes sorting on alerts tables when dealing with grouped alerts.

dashboard/dashboard/elements/alerts-page-test.html

Index: dashboard/dashboard/elements/alerts-page-test.html
diff --git a/dashboard/dashboard/elements/alerts-page-test.html b/dashboard/dashboard/elements/alerts-page-test.html
index 433b10698b4468ed91d1c439d90e46717eb6fbb4..816bdda7f512bd3fc7681e0d332f1f5c035b6dd9 100644
--- a/dashboard/dashboard/elements/alerts-page-test.html
+++ b/dashboard/dashboard/elements/alerts-page-test.html
@@ -118,6 +118,63 @@ tr.b.unittest.testSuite(function() {
           'percent_changed': '1.4%',
           'test': 'bitrate_stats_without_min_transmit_bitrate\/bitrate_kbps',
           'recovered': false
+        },
+        {
+          'end_revision': 13465,
+          'dashboard_link': 'http://do/not/click/me',
+          'bug_id': null,
+          'key': 'agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgitKhswoM',
+          'date': '2016-07-14',
+          'median_before_anomaly': 34.51,
+          'bisect_status': null,
+          'testsuite': 'webrtc_perf_tests',
+          'group': 'agxzfmNocm9tZXBlcmZyFwsSCkFsZXJ0R3JvdXAYgICgiovavgoN',
+          'start_revision': 13465,
+          'bot': 'hwebrtc-linux-large-tests',
+          'improvement': false,
+          'median_after_anomaly': 34.0396039604,
+          'master': 'ChromiumPerf',
+          'percent_changed': '1.6%',
+          'test': 'bitrate_stats_without_min_transmit_bitrate\/bitrate_kbps',
+          'recovered': false
+        },
+        {
+          'end_revision': 13465,
+          'dashboard_link': 'http://do/not/click/me',
+          'bug_id': null,
+          'key': 'agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgitKhswoM',
+          'date': '2016-07-14',
+          'median_before_anomaly': 34.51,
+          'bisect_status': null,
+          'testsuite': 'webrtc_perf_tests',
+          'group': 'agxzfmNocm9tZXBlcmZyFwsSCkFsZXJ0R3JvdXAYgICgiovavgoN',
+          'start_revision': 13465,
+          'bot': 'xwebrtc-linux-large-tests',
+          'improvement': false,
+          'median_after_anomaly': 34.0396039604,
+          'master': 'ChromiumPerf',
+          'percent_changed': '3.4%',
+          'test': 'bitrate_stats_without_min_transmit_bitrate\/bitrate_kbps',
+          'recovered': false
+        },
+        {
+          'end_revision': 13465,
+          'dashboard_link': 'http://do/not/click/me',
+          'bug_id': null,
+          'key': 'agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgitKhswoM',
+          'date': '2016-07-14',
+          'median_before_anomaly': 34.51,
+          'bisect_status': null,
+          'testsuite': 'webrtc_perf_tests',
+          'group': 'agxzfmNocm9tZXBlcmZyFwsSCkFsZXJ0R3JvdXAYgICgiovavgoN',
+          'start_revision': 13465,
+          'bot': 'mwebrtc-linux-large-tests',
+          'improvement': false,
+          'median_after_anomaly': 34.0396039604,
+          'master': 'ChromiumPerf',
+          'percent_changed': '1.2%',
+          'test': 'bitrate_stats_without_min_transmit_bitrate\/bitrate_kbps',
+          'recovered': false
         }
       ],
       'stoppage_alert_list': [