analysis/appengine/template: remove extra whitespace

Change-Id: If015d2cf0998b357f829e8e136bec5f901aa6091
Reviewed-on: https://go-review.googlesource.com/35930Reviewed-by: Russ Cox <rsc@golang.org>

analysis/appengine/template/compare.html

@@ -46,7 +46,7 @@ table.benchstat td, table.benchstat th {
   padding-right: 2px;
   padding-bottom: 2px;
 }
-#labels > tbody > tr:last-child th, #labels > tbody > tr:last-child td {
+#labels > tbody > tr:last-child > th, #labels > tbody > tr:last-child > td {
   padding-bottom: 1em;
 }
 #labels tbody tr:first-child th, #benchstat {