Add option for hiding Confidence Interval Delta on the performance tests results...

Add option for hiding Confidence Interval Delta on the performance tests results page
https://bugs.webkit.org/show_bug.cgi?id=130483

Reviewed by Ryosuke Niwa.

I've found it useful to hide the confidence interval delta from the results table
sometimes, for example on copying data, or for a clearer look. This patch introduces
a new button for it on the local results page.

* resources/results-template.html:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@166038 268f45cc-cd09-0410-ab3c-d52691b4dbfc