tests/functional: skip vulkan tests with nVidia

tests/functional: skip vulkan tests with nVidia

While running the new GPU tests it was noted that the proprietary
nVidia driver barfed when run under the sanitiser:

  2025-02-20 11:13:08,226: [11:13:07.782] Output 'headless' attempts
  EOTF mode SDR and colorimetry mode default.
  2025-02-20 11:13:08,227: [11:13:07.784] Output 'headless' using color
  profile: stock sRGB color profile

  and that's the last thing it outputs.

  The sanitizer reports that when the framework sends the SIGTERM
  because of the timeout we get a write to a NULL pointer (but
  interesting not this time in an atexit callback):

  UndefinedBehaviorSanitizer:DEADLYSIGNAL
  ==471863==ERROR: UndefinedBehaviorSanitizer: SEGV on unknown address
  0x000000000000 (pc 0x7a18ceaafe80 bp 0x000000000000 sp 0x7ffe8e3ff6d0
  T471863)
  ==471863==The signal is caused by a WRITE memory access.
  ==471863==Hint: address points to the zero page.
      #0 0x7a18ceaafe80
  (/lib/x86_64-linux-gnu/libnvidia-eglcore.so.535.183.01+0x16afe80)
  (BuildId: 24b0d0b90369112e3de888a93eb8d7e00304a6db)
      #1 0x7a18ce9e72c0
  (/lib/x86_64-linux-gnu/libnvidia-eglcore.so.535.183.01+0x15e72c0)
  (BuildId: 24b0d0b90369112e3de888a93eb8d7e00304a6db)
      #2 0x7a18ce9f11bb
  (/lib/x86_64-linux-gnu/libnvidia-eglcore.so.535.183.01+0x15f11bb)
  (BuildId: 24b0d0b90369112e3de888a93eb8d7e00304a6db)
      #3 0x7a18ce6dc9d1
  (/lib/x86_64-linux-gnu/libnvidia-eglcore.so.535.183.01+0x12dc9d1)
  (BuildId: 24b0d0b90369112e3de888a93eb8d7e00304a6db)
      #4 0x7a18e7d15326 in vrend_renderer_create_fence
  /usr/src/virglrenderer-1.0.0-1ubuntu2/obj-x86_64-linux-gnu/../src/vrend_renderer.c:10883:26
      #5 0x55bfb6621871 in virtio_gpu_virgl_process_cmd

The #dri-devel channel confirmed:

  <digetx> stsquad: nv driver is known to not work with venus, don't use
      it for testing

So lets skip running the test to avoid known failures. As we now use
vulkaninfo to probe we also need to handle the case where there is no
Vulkan driver configured for the hardware.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Cc: Dmitry Osipenko <dmitry.osipenko@collabora.com>
[AJB: also skip if vulkaninfo can't find environment]
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20250304222439.2035603-6-alex.bennee@linaro.org>