meson: tests: add file access test setup

meson: tests: add file access test setup

We need to modify check-file-access.py to be usable as wrapper for
libvirt tests. This way we can run the tests using this command:

    meson test --setup access

which will run all tests using check-file-access.py as a wrapper.

With autotools all file access are written into single file for all
tests and compared once the whole test suite is done.

With Meson we will compare the file access after every single test
because it is used as wrapper now. That requires writing the file
access into separate files for every single test as they are executed
in parallel.

Since the wrapper is used for all tests in Meson including tests outside
of tests directory we have to check for presence of the output file.
We should also cleanup after ourselves.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Neal Gompa <ngompa13@gmail.com>