parser: if closing square bracket not found, stop looking for it again

This solves #5584, where the fuzzing would take hours without this.

src/uucore/src/lib/parser/parse_glob.rs

@@ -18,7 +18,9 @@ fn fix_negation(glob: &str) -> String {
     while i + 3 < chars.len() {
         if chars[i] == '[' && chars[i + 1] == '^' {
             match chars[i + 3..].iter().position(|x| *x == ']') {
-                None => (),
+                None => {
+                    break;
+                }
                 Some(j) => {
                     chars[i + 1] = '!';
                     i += j + 4;