During rerun, fix full test benchmark path to be the same as only_test

When doing reruns for the full test suite, the reruns benchmark name is 
being incorrectly reported to the server.  This adds the benchmark’s path
back on when reruns happen in the full test suite mode.

git-svn-id: https://llvm.org/svn/llvm-project/lnt/trunk@218678 91177308-0d34-0410-b5e6-96231b3b80d8