iotests: strip subdir path when listing tests

iotests: strip subdir path when listing tests

When asking 'check' to list individual tests by invoking it in dry run
mode, it prints the paths to the tests relative to the base of the
I/O test directory.

When asking 'check' to run an individual test, however, it mandates that
only the unqualified test name is given, without any path prefix. This
inconsistency makes it harder to ask for a list of tests and then invoke
each one.

Thus the test listing code is change to flatten the test names, by
printing only the base name, which can be directly invoked.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Acked-by: Hanna Czenczek <hreitz@redhat.com>
Tested-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20230303160727.3977246-4-berrange@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20230315174331.2959-21-alex.bennee@linaro.org>