test: add NumberFormat resolvedOptions test

Add a regression test for NumberFormat resolvedOptions. PR-URL: #39401 Refs: #39050 Reviewed-By: Michaël Zasso <[email protected]> Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: Tobias Nießen <[email protected]> Backport-PR-URL: #39051

Author: richardlau

test/parallel/test-intl.js

@@ -104,6 +104,13 @@ if (!common.hasIntl){
 constnumberFormat=newIntl.NumberFormat(['en']).format(12345.67890);
 assert.strictEqual(numberFormat,'12,345.679');
 }
+// Number format resolved options
+{
+constnumberFormat=newIntl.NumberFormat('en-US',{style: 'percent'});
+constresolvedOptions=numberFormat.resolvedOptions();
+assert.strictEqual(resolvedOptions.locale,'en-US');
+assert.strictEqual(resolvedOptions.style,'percent');
+}
 // Significant Digits
 {
 constloc=['en-US'];