Skip this performance regression test.

The test measures things on the order of 20ms.  On a loaded machine, we
have seen enough variation that the test would fail.

--- grep-2.22/tests/long-pattern-perf	2016-01-03 12:52:38.491575007 +0100
+++ grep-2.22/tests/long-pattern-perf	2016-01-03 12:53:39.768464687 +0100
@@ -16,6 +16,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+exit 77
 . "${srcdir=.}/init.sh"; path_prepend_ ../src
 
 fail=0
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<div class='path'>path: <a href='/guix/log/?id=81a24d3050b0f2b221e5cc5756fc26f4cdf1876c'>root</a>/<a href='/guix/log/tests?id=81a24d3050b0f2b221e5cc5756fc26f4cdf1876c'>tests</a>/<a href='/guix/log/tests/guix-graph.sh?id=81a24d3050b0f2b221e5cc5756fc26f4cdf1876c'>guix-graph.sh</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/tests/guix-graph.sh?id=81a24d3050b0f2b221e5cc5756fc26f4cdf1876c&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-09-26 17:36:57 +0200'>2023-09-26</span></td><td><a href='/guix/commit/tests/guix-graph.sh?id=7f3ebd6dbcae830e60b78d6bab8f1dbad90ba3a8'>tests: Adjust ‘guix graph --path’ test to latest Emacs changes.</a><span class='msg-avail'>...<span class='msg-tooltip'>This is a followup to 3349a50d700a2112a31ac4ce6cc6639d3b4cf1e2.

* tests/guix-graph.sh: Adjust ‘path’.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2023-04-28 19:50:39 +0200'>2023-04-28</span></td><td><a href='/guix/commit/tests/guix-graph.sh?id=ee88acc6e22595bbf4a6f07332ed4308d6a6e3cf'>tests: guix-graph.sh: Fix expected path from emacs to libffi.</a><span class='msg-avail'>...<span class='msg-tooltip'>* tests/guix-graph.sh: Change the expected path from emacs to libffi.  `guix
graph --path` outputs only one possible path, and the one it outputs for this
case has changed.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Josselin Poiret</td></tr>
<tr><td><span title='2023-04-21 16:16:38 +0200'>2023-04-21</span></td><td><a href='/guix/commit/tests/guix-graph.sh?id=37dd69b44511dc73eb04bdebe8d82c9a0386338e'>tests: Fix checks for expected failures.</a><span class='msg-avail'>...<span class='msg-tooltip'>Addresses &lt;https://issues.guix.gnu.org/62406&gt;.

With 'set -e', a return status inverted with '!' does not cause the shell to
exit immediately.  Instead use '&amp;&amp; false' to indicate an expected failure.

* tests/guix-archive.sh, tests/guix-build-branch.sh, tests/guix-build.sh,
tests/guix-daemon.sh, tests/guix-download.sh,
tests/guix-environment-container.sh, tests/guix-environment.sh,
tests/guix-gc.sh, tests/guix-git-authenticate.sh, tests/guix-graph.sh,
tests/guix-hash.sh, tests/guix-home.sh, tests/guix-pack-relocatable.sh,
tests/guix-pack.sh, tests/guix-package-aliases.sh, tests/guix-package-net.sh,
tests/guix-package.sh, tests/guix-refresh.sh, tests/guix-shell.sh,
tests/guix-style.sh, tests/guix-system.sh: Replace uses of '! ...' with
'... &amp;&amp; false' or `test ! ...` as appropriate.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Eric Bavier</td></tr>