--valgrind doesn't work
Running piglit CL tests with the --valgrind option gives a results file with all tests marked as skipped:
$ piglit run --valgrind cl cl.results
"result": "skip",
"command": "/usr/lib/x86_64-linux-gnu/piglit/bin/valgrind",
"out": "An internal exception that should have been handled was not:\nTest executable not found.\n",