ci/lava: Fix Gitlab section rendering
LAVA splits the DUT log lines with `\r` in them. Unfortunately, it
breaks the Gitlab section line syntax when the HWCI script calls it
since it is a oneliner.
This commit changes the` fix_lava_gitlab_section_log` function to a
stateful generator that can merge lines that respects two consecutive
patterns.
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/7703
Signed-off-by: Guilherme Gallo <guilherme.gallo@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20051>