The Unicode tests were split into five files (#2889) so they could run
in parallel. After #5418 they take ~20 s together (unoptimized), so one
file is enough. This removes four copies of the check helpers and the
progress output, whose hard-coded totals were stale, and drops
doctest::skip() so JSON_FastTests configurations run them too. The
raised timeout for test-unicode4 is no longer needed.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Niels Lohmann
9ffd033af7