CI: ignore most precision.fpexr tests

The test requires a framebuffer configuration that softpipe doesn't support
and leads to inconsistent results.
When run directly on softpipe all these tests fail because of the framebuffer
error, but with virglrenderer we don't report this error and the results that
are read back might be random.

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Reviewed-by: Gurchetan Singh <gurchetansingh@chromium.org>
11 jobs for ci-ignore-most-fpexr in 42 minutes and 40 seconds (queued for 1 minute and 26 seconds)