make upstream test-suite work again with i18n patch

New tests in tests/pr/pr-tests.pl have names which - with the suffix
"-mb" for the i18n test - become "too long (>30)".  I adjusted
'tests/Coreutils.pm' accordingly.

coreutils-i18n.patch

@@ -2895,6 +2895,20 @@ index 8f6e973..752797a 100644
    skip_chars = 0;
    skip_fields = 0;
    check_chars = SIZE_MAX;
+diff --git a/tests/Coreutils.pm b/tests/Coreutils.pm
+index dc6b132..a2abc6d 100644
+--- a/tests/Coreutils.pm
++++ b/tests/Coreutils.pm
+@@ -264,6 +264,9 @@ sub run_tests ($$$$$)
+       # Yes, this is an arbitrary limit.  If it causes trouble,
+       # consider removing it.
+       my $max = 30;
++      # The downstream i18n multi-byte tests have a "-mb" suffix.
++      # Therefore add 3 to the maximum test name length.
++      $max += 3;
+       if ($max < length $test_name)
+         {
+           warn "$program_name: $test_name: test name is too long (> $max)\n";
 diff --git a/tests/i18n/sort.sh b/tests/i18n/sort.sh
 new file mode 100755
 index 0000000..26c95de