Change the userdiff test to list the builtin drivers via the
test-tool, using the new for_each_userdiff_driver() API function.
This gets rid of the need to modify this part of the test every time a
new pattern is added, see 2ff6c34612 (userdiff: support Bash,
2020-10-22) and 09dad9256a (userdiff: support Markdown, 2020-05-02)
for two recent examples.
I only need the "list-builtin-drivers "argument here, but let's add
"list-custom-drivers" and "list-drivers" too, just because it's easy.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
