Remove a sub-minute offset test

There was one remaining Temporal test that was parsing an ISO string
with a sub-minute offset into a Temporal.TimeZone. A polyfill bug was
allowing this test case to pass, even though after
tc39/proposal-temporal#2607 it should have failed.

This commit removes the bad test case.

test/staging/Temporal/Regex/old/timezone.js

@@ -43,7 +43,6 @@ function generateTest(dateTimeString, zoneString, expectedName) {
 });
 generateTest("1976-11-18T15:23", "z", "UTC");
 test("1976-11-18T15:23:30,1234Z", "UTC");
-test("1976-11-18T15:23-04:00:00,000000000", "-04:00");
 test("1976-11-18T15:23+000000,0[UTC]", "UTC");
 [
   "\u221204:00",