This will hopefully give us more information about why some tests are
intermittently timing out.
Only in build jobs using the x86_build docker image for now, since
those are where we're currently seeing most such timeouts. But may
expand this later if it provides the expected benefits.
v2:
* Add comment about why we test for and use /usr/bin/time explicitly.
Acked-by: Eric Engestrom <eric@engestrom.ch> # v1
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8776>