More CTS Coverage Build Improvements

Bug 3245588

The build server couldn't display the XML report with the XSL
transformation. Thus, when you clicked on the XML file, you
would just see the raw XML which wasn't very useful. So make
the report generator output a single HTML file by transforming
the XML into HTML in code.

Change-Id: Ie8b585551e4150f360a6622b3c6f7298ebd0a1e8