glsl/tests: Make the tests skip on Android binary execution failures.

We don't have a suitable exe wrapper for running them, and the missing
linker is throwing return code 255 instead of an ENOEXEC.  Catch it and
return skip from the tests.

Reviewed-by: Kristian H. Kristensen <hoegsberg@google.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6700>
3 files changed