Fix Gnulib test failures showing up on ARMv7:

  https://issues.guix.gnu.org/49459

This is a backport of this Gnulib commit:

  commit 175e0bc72808d564074c4adcc72aeadb74adfcc6
  Author: Paul Eggert <eggert@cs.ucla.edu>
  Date:   Thu Aug 27 17:52:58 2020 -0700

      perror, strerror_r: remove unportable tests

      Problem reported by Florian Weimer in:
      https://lists.gnu.org/r/bug-gnulib/2020-08/msg00220.html
      * tests/test-perror2.c (main):
      * tests/test-strerror_r.c (main): Omit unportable tests.

diff --git a/tests/test-perror2.c b/tests/test-perror2.c
index 1d14eda7be..c6214dd25c 100644
--- a/gnulib-tests/test-perror2.c
+++ b/gnulib-tests/test-perror2.c
@@ -79,9 +79,6 @@ main (void)
     errno = -5;
     perror ("");
     ASSERT (!ferror (stderr));
-    ASSERT (msg1 == msg2 || msg1 == msg4 || STREQ (msg1, str1));
-    ASSERT (msg2 == msg4 || STREQ (msg2, str2));
-    ASSERT (msg3 == msg4 || STREQ (msg3, str3));
     ASSERT (STREQ (msg4, str4));
 
     free (str1);
diff --git a/tests/test-strerror_r.c b/tests/test-strerror_r.c
index b11d6fd9f6..c1dbcf837b 100644
--- a/gnulib-tests/test-strerror_r.c
+++ b/gnulib-tests/test-strerror_r.c
@@ -165,9 +165,6 @@ main (void)
 
     strerror_r (EACCES, buf, sizeof buf);
     strerror_r (-5, buf, sizeof buf);
-    ASSERT (msg1 == msg2 || msg1 == msg4 || STREQ (msg1, str1));
-    ASSERT (msg2 == msg4 || STREQ (msg2, str2));
-    ASSERT (msg3 == msg4 || STREQ (msg3, str3));
     ASSERT (STREQ (msg4, str4));
 
     free (str1);
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<tr><td><span title='2023-05-31 17:23:21 +0200'>2023-05-31</span></td><td><a href='/guix/commit/po/packages/da.po?id=8e9e6a6482f3ba98d1cdcad344ee488e8751fee7'>nls: Update translations.</a><span class='msg-avail'>...<span class='msg-tooltip'>* doc/guix-cookbook.texi (Top): Mention Slovak.
</span></span></td><td>Florian Pelz</td></tr>
<tr><td><span title='2023-03-07 21:14:57 +0100'>2023-03-07</span></td><td><a href='/guix/commit/po/packages/da.po?id=d333958763b0840c4cd895601b079b68358a6a46'>nls: Update translations.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2022-12-04 22:25:23 +0100'>2022-12-04</span></td><td><a href='/guix/commit/po/packages/da.po?id=2e75b328b6bbdadbffe5b643a4891b5026a0defd'>nls: Update translations.</a><span class='msg-avail'>...<span class='msg-tooltip'>po/packages/vi.po: New file.
po/packages/LINGUAS: Add it.
</span></span></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2022-11-04 10:56:38 +0100'>2022-11-04</span></td><td><a href='/guix/commit/po/packages/da.po?id=a65ce9dd500460af4f97e7398fb35dd817f4c677'>nls: Update translations.</a><span class='msg-avail'>...<span class='msg-tooltip'>* po/guix/lt.po: New file.
* po/guix/LINGUAS: Add lt.
</span></span></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2022-10-06 08:20:20 +0200'>2022-10-06</span></td><td><a href='/guix/commit/po/packages/da.po?id=70fc8f6d619ce9f16a8cc0bbb10a011bd3a9997a'>nls: Update translations.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2022-09-04 16:52:02 +0200'>2022-09-04</span></td><td><a href='/guix/commit/po/packages/da.po?id=77e3042aef6d8e519d016555464e466399318b4f'>nls: Update translations.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2022-08-10 23:32:24 +0200'>2022-08-10</span></td><td><a href='/guix/commit/po/packages/da.po?id=aacbe59fbceb8a93ecb68fed8581dfdd70dafc11'>nls: Update translations.</a><span class='msg-avail'>...<span class='msg-tooltip'>po/guix/bn.po: New file.
po/guix/LINGUAS: Add it.
</span></span></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2022-07-09 21:49:34 +0200'>2022-07-09</span></td><td><a href='/guix/commit/po/packages/da.po?id=e0d47d8facafb6d6c04741bbf30eefbc68aaefb9'>nls: Update translations.</a><span class='msg-avail'>...<span class='msg-tooltip'>po/guix/tr.po: New file.
po/guix/LINGUAS: Add it.
</span></span></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2022-06-04 17:42:54 +0200'>2022-06-04</span></td><td><a href='/guix/commit/po/packages/da.po?id=809c57c872a6dd48007d1abf6d7f3dd1482ec53a'>nls: Update translations.</a><span class='msg-avail'>...<span class='msg-tooltip'>po/packages/tr.po: New file.
po/packages/LINGUAS: Add it.
</span></span></td><td>Julien Lepiller</td></tr>