vfio: selftests: Move run.sh into scripts directory

vfio: selftests: Move run.sh into scripts directory

Move run.sh in a new sub-directory scripts/. This directory will be used
to house various helper scripts to be used by humans and automation for
running VFIO selftests.

Opportunistically also switch run.sh from TEST_PROGS_EXTENDED to
TEST_FILES. The former is for actual test executables that are just not
run by default. TEST_FILES is a better fit for helper scripts.

No functional change intended.

Reviewed-by: Alex Mastro <amastro@fb.com>
Tested-by: Alex Mastro <amastro@fb.com>
Reviewed-by: Raghavendra Rao Ananta <rananta@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20251126231733.3302983-2-dmatlack@google.com
Signed-off-by: Alex Williamson <alex@shazbot.org>