tests: more automated quote adjustment

Relax initial regexp to match more instances, but add a
filter to avoid some invalid conversions.  Run this:

git grep -l "\`[^']*'" tests | xargs perl -pi -e '$q=q"'\''";' \
  -e '$q="$q\\$q$q"; /(= ?\`|\`expr|\`echo|\Q$q\E)/ and next;' \
  -e ' s/\`([^'\''"]*?'\'')/'\''$1/g'
The last disjunct in the above (...) filter is to exempt
any line that contains this string: '\''
With quoting like that, converting a ` to ' is likely to cause trouble,
so we'll handle those manually.  Here are three examples where
the exemption is required:

  *': `link-to-dir/'\'': hard link not allowed for directory'*) ;;
  printf 'creating file `%s'\''\n' $f
  'mv: inter-device move failed: `%s'\'' to `%s'\'';'\

1 files changed, 2 insertions, 2 deletions

diff --git a/tests/misc/sha1sum-vec b/tests/misc/sha1sum-vec
index 4c7c06afd..d7b5e0d8e 100755
--- a/tests/misc/sha1sum-vec
+++ b/tests/misc/sha1sum-vec
@@ -495,8 +495,8 @@ sub binary_expand ($$)
   defined $n && defined $b or die "$test_name: too few args\n";
   my @a = split ' ', $rest, $n + 1;
   my $caret = pop @a;
-  $caret eq '^' or die "test $test_name: @a missing `^'\n";
-  $b eq '1' || $b eq '0' or die "test $test_name: bad `b'=$b\n";
+  $caret eq '^' or die "test $test_name: @a missing '^'\n";
+  $b eq '1' || $b eq '0' or die "test $test_name: bad 'b'=$b\n";
   my $n_bad = @a;
   @a == $n or
     die "test $test_name: wrong number of args (expected $n, found $n_bad)\n";