bug#33653: 27.0.50; Change Gnus obarrays-as-hash-tables into real hash tables

[Katsumi Yamaoka]

One more regression. :)

In the group buffer the `j' command (`gnus-group-jump-to-group')
does not work for a group that is not activated yet.  The point
goes to the top.  Such a group will appear with the `*' mark by
the `l' or the `L' command like the followig:

       *: nntp+gmane:gmane.emacs.devel

Similarly the "#" mark put in front of a marked such group will
not disappear after processing a certain job (normally
`gnus-group-get-new-news-this-group' on me) as follows:

  #    *: nntp+gmane:gmane.emacs.devel
  ↓↓↓
  #  168: nntp+gmane:gmane.emacs.devel

The cause is the same; such non-activated groups are not listed
in `gnus-active-hashtb':

(gethash "nntp+gmane:gmane.emacs.devel" gnus-active-hashtb)
 => nil

But in Gnus bundled with Emacs 26.1.92 it returns a group name
symbol, though its value (i.e., active) is nil:

(gnus-intern-safe "nntp+gmane:gmane.emacs.devel" gnus-active-hashtb)
 => nntp+gmane:gmane\.emacs\.devel
(symbol-value
 (gnus-intern-safe "nntp+gmane:gmane.emacs.devel" gnus-active-hashtb))
 => nil

In my Gnus, there are many non-activated groups at just after
lauching Gnus with the prefix arg `1', because I set the group
level `1' to the groups normally used and larger level to the
others.  In the starting time of work, my habit is to check
mails in the active groups for a while and then activate and
check groups of larger level.

Running `gnus-group-get-new-news-this-group' again on a group in
question helps (the "#" mark disappears) but I wish it could work
as before.  How about making the value for an inactive group in
hashtb to `t' or something, that means the group exists but not
activated?

Regards,