BUG/MEDIUM: h3: Declare absolute URI as normalized when a :authority is found

BUG/MEDIUM: h3: Declare absolute URI as normalized when a :authority is found

Since commit 2c3d656f8 ("MEDIUM: h3: use absolute URI form with
:authority"), the absolute URI form is used when a ':authority'
pseudo-header is found. However, this URI was not declared as normalized
internally.  So, when the request is reformated to be sent to an h1 server,
the absolute-form is used instead of the origin-form. It is unexpected and
may be an issue for some servers that could reject the request.

So, now, we take care to set HTX_SL_F_HAS_AUTHORITY flag on the HTX message
when an authority was found and HTX_SL_F_NORMALIZED_URI flag is set for
"http" or "https" schemes.

No backport needed because the commit above must not be backported. It
should fix a regression reported on the 3.2-dev17 in issue #2977.

This commit depends on "BUG/MINOR: h3: Set HTX flags corresponding to the
scheme found in the request".