Fix bugs when replacing characters with space (#18455)

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

benchmarks/trim-indentation.js

@@ -18,7 +18,6 @@ for (const size of [1, 1e1, 1e2]) {
         (regexp) => () =>
           text.replace(regexp, "")
       )(/[ \t]*$/gu),
-      // eslint-disable-next-line require-unicode-regexp
       "RegExp (no `u` flag)": () => text.replace(/[ \t]*$/, ""),
     },
   );