mesa/tests: add missing dep_thread

Fixes: f8c27c27 ("state_tracker: Move the format test out to be an actual unit test.")
Signed-off-by: Eric Engestrom <eric.engestrom@intel.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Tested-by: Vinson Lee <vlee@freedesktop.org>
13 jobs for !1391 with mesa-test-dep_thread in 9 seconds (queued for 1 second)
detached
Status Job ID Name Coverage
  Containers Build
canceled #434007
debian

00:00:09

 
  Build+Test
skipped #434016
meson-arm64
skipped #434015
meson-armhf
skipped #434009
meson-clang
skipped #434013
meson-clover
skipped #434017
meson-i386
skipped #434012
meson-main
skipped #434008
meson-swr-glvnd
skipped #434014
meson-vulkan
skipped #434019
scons-llvm
skipped #434018
scons-nollvm
skipped #434010
scons-swr
skipped #434011
scons-win64