benchmark: fix getStringWidth() benchmark

8fb5fe2 broke the benchmark for
getStringWidth(). This fixes it up by updating the argument to
`require()` to retrieve `getStringWidth()` from the new internal module
location.

PR-URL: #31476
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Author: Trott

benchmark/misc/getstringwidth.js

@@ -12,7 +12,7 @@ const bench = common.createBenchmark(main, {
 function main({ n, type }) {
   // Default value for testing purposes.
   type = type || 'ascii';
-  const { getStringWidth } = require('internal/readline/utils');
+  const { getStringWidth } = require('internal/util/inspect');
 
   const str = ({
     ascii: 'foobar'.repeat(100),