Remove test that doesn't match RFC 3339 duration grammar

Removing pending clariication in the JSON schema spec.

Author: ssilverman

tests/draft2019-09/optional/format/duration.json

@@ -68,11 +68,6 @@
               "data": "PT1M",
               "valid": true
           },
-          {
-              "description": "elements may be omitted if their value is zero",
-              "data": "PT1H1S",
-              "valid": true
-          },
           {
               "description": "one and a half days, in hours",
               "data": "PT36H",