Disable non-deterministic flaky test (#4295)

__tests__/lib/string.test.ts

@@ -142,7 +142,8 @@ describe('makeRecordUri', () => {
   })
 })
 
-describe('ago', () => {
+// FIXME: Reenable after fixing non-deterministic test.
+describe.skip('ago', () => {
   const oneYearDate = new Date(
     new Date().setMonth(new Date().getMonth() - 11),
   ).setDate(new Date().getDate() - 28)