[utils] Generate html reports with the code coverage utility script

Instead of extracting raw coverage mappings into an artifact directory,
actually generate useful html reports for a given list of binaries with
symbol demangling turned on.

No tests, but this is actively being used to drive the (still nascent)
coverage bot.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275927 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed