test: use regex error checks in test-util-format

Replace constructor with regular expression for second argument
to assert.throws() in test-util-format.

PR-URL: #14299
Reviewed-By: Rich Trott <[email protected]>
Reviewed-By: Gibson Fahnestock <[email protected]>
Reviewed-By: Benjamin Gruenbaum <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Tobias Nießen <[email protected]>
Reviewed-By: Refael Ackermann <[email protected]>
Reviewed-By: Gireesh Punathil <[email protected]>

Author: superwoods

test/parallel/test-util-format.js

@@ -46,7 +46,7 @@ assert.strictEqual(util.format('%s', symbol), 'Symbol(foo)');
 assert.strictEqual(util.format('%j', symbol), 'undefined');
 assert.throws(function() {
   util.format('%d', symbol);
-}, TypeError);
+}, /^TypeError: Cannot convert a Symbol value to a number$/);
 
 // Number format specifier
 assert.strictEqual(util.format('%d'), '%d');