[Piglit] What happened to concurrency?

[Marek Olšák]

Hi,

I have updated piglit today (c5060a8..3456230) and found out that
concurrency is broken. When I run piglit, about 5000 tests run
concurrently with all 4 CPU cores utilized and then it drops to 1 CPU
core for the rest of the run (there are 16000 tests or so) and takes a
very long time to finish.

No idea what happened there, but I'm pretty sure concurrency should be
enabled for about 90% tests.

Marek