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
'><form method='get'>
<input type='hidden' name='id' value='360a9f0a2f94053ad11bcec43710ef68660082e9'/><select name='h' onchange='this.form.submit();'>
<option value='koszko' selected='selected'>koszko</option>
<option value='koszko-scripts'>koszko-scripts</option>
</select> <input type='submit' value='switch'/></form></td></tr>
<tr><td class='sub'>Wojtek's customized Guix</td><td class='sub right'></td></tr></table>
<table class='tabs'><tr><td>
<a href='/guix/about/'>about</a><a href='/guix/'>summary</a><a href='/guix/refs/?id=360a9f0a2f94053ad11bcec43710ef68660082e9'>refs</a><a class='active' href='/guix/log/gnu/tests'>log</a><a href='/guix/tree/gnu/tests?id=360a9f0a2f94053ad11bcec43710ef68660082e9'>tree</a><a href='/guix/commit/gnu/tests?id=360a9f0a2f94053ad11bcec43710ef68660082e9'>commit</a><a href='/guix/diff/gnu/tests?id=360a9f0a2f94053ad11bcec43710ef68660082e9'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/tests'>
<input type='hidden' name='id' value='360a9f0a2f94053ad11bcec43710ef68660082e9'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=360a9f0a2f94053ad11bcec43710ef68660082e9'>root</a>/<a href='/guix/log/gnu?id=360a9f0a2f94053ad11bcec43710ef68660082e9'>gnu</a>/<a href='/guix/log/gnu/tests?id=360a9f0a2f94053ad11bcec43710ef68660082e9'>tests</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/gnu/tests?id=360a9f0a2f94053ad11bcec43710ef68660082e9&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2024-06-02 15:06:16 +0400'>2024-06-02</span></td><td><a href='/guix/commit/gnu/tests?id=eac5171246da875f5996621c5329c833fd85b891'>Revert "services: home: Use pairs instead of lists."</a><span class='msg-avail'>...</span></td><td>Andrew Tropin</td></tr>
<tr><td><span title='2024-06-02 13:38:52 +0400'>2024-06-02</span></td><td><a href='/guix/commit/gnu/tests?id=dbeef44f3c520816251bde74c1005915a637e1ef'>services: home: Use pairs instead of lists.</a><span class='msg-avail'>...</span></td><td>Andrew Tropin</td></tr>
<tr><td><span title='2024-05-27 10:26:24 +0300'>2024-05-27</span></td><td><a href='/guix/commit/gnu/tests?id=4c39f6edebd2a3601c7b75adaf0426c72246b011'>tests: install: Use a default qemu machine for arm architectures.</a><span class='msg-avail'>...</span></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2024-05-27 10:26:24 +0300'>2024-05-27</span></td><td><a href='/guix/commit/gnu/tests?id=f2bfe1d06529c158ced37f2239eb477756661ebf'>tests: install: Add support for aarch64 UEFI tests.</a><span class='msg-avail'>...</span></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2024-05-27 10:26:24 +0300'>2024-05-27</span></td><td><a href='/guix/commit/gnu/tests?id=c0610dfb1aa2a58396b93125bfb7ade3e6dd040f'>gnu: Use new ovmf firmware packages.</a><span class='msg-avail'>...</span></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2024-05-25 15:34:57 +0200'>2024-05-25</span></td><td><a href='/guix/commit/gnu/tests?id=be868f69aae8fc0a33edf5d98974e99208268aad'>gnu: Add tests for oci-container-service-type.</a><span class='msg-avail'>...</span></td><td>Giacomo Leidi</td></tr>
<tr><td><span title='2024-04-17 12:13:03 +0200'>2024-04-17</span></td><td><a href='/guix/commit/gnu/tests?id=59bb53823e6babb2d50e246d312879980c7988c9'>services: Add the Guix Home service.</a><span class='msg-avail'>...</span></td><td>Richard Sent</td></tr>
<tr><td><span title='2024-04-15 09:52:44 +0100'>2024-04-15</span></td><td><a href='/guix/commit/gnu/tests?id=027419626f171cdccf9c4a77686840141ea502eb'>gnu: tests: Add system test for sddm.</a><span class='msg-avail'>...</span></td><td>Richard Sent</td></tr>
<tr><td><span title='2024-04-08 00:05:48 +0200'>2024-04-08</span></td><td><a href='/guix/commit/gnu/tests?id=a7f15c9ecffc1762f5886fb5a2a14490e2994c8c'>reconfigure: /run/current-system points to generation.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2024-03-17 12:53:21 +0100'>2024-03-17</span></td><td><a href='/guix/commit/gnu/tests?id=85083527ddb5d4672ae069590aa65ec6ebce96e1'>gnu: tests: Fix prosody system test.</a><span class='msg-avail'>...</span></td><td>Carlo Zancanaro</td></tr>