mesa: stop trying new filenames if the filename existing is not the issue

Signed-off-by: Eric Engestrom <eric.engestrom@intel.com>
Reviewed-by: Kristian H. Kristensen <hoegsberg@google.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
10 jobs for !1161 with mesa-shader_test-race in 8 minutes and 41 seconds (queued for 1 second)
detached
Status Job ID Name Coverage
  Containers Build
passed debian #388819

00:00:18

 
  Build+Test
passed meson-clang #388821

00:08:22

passed meson-clover #388825

00:05:28

passed meson-main #388824

00:04:00

passed meson-swr-glvnd #388820

00:02:41

passed meson-vulkan #388826

00:00:44

passed scons-llvm #388828

00:05:17

passed scons-nollvm #388827

00:02:39

passed scons-swr #388822

00:03:32

passed scons-win64 #388823

00:03:01