TimeZone serialization

From the JSON-B specification:

> The serialization format of `java.util.TimeZone` and `SimpleTimeZone` is `NormalizedCustomID` as specified in `java.util.TimeZone`.

The `NormalizedCustomID` format is defined in the JavaDoc for [TimeZone](https://docs.oracle.com/javase/8/docs/api/java/util/TimeZone.html#NormalizedCustomID). A valid normalized custom ID is, for example, GMT+01:00. The test [DatesMappingTest#testLongTimeZoneMapping](https://github.com/eclipse-ee4j/jsonb-api/blob/9c248fe914349d8d1dae7d9f172bb33feb2b9aea/tck/src/main/java/jakarta/json/bind/tck/defaultmapping/dates/DatesMappingTest.java#L304-L309) serializes `TimeZone.getTimeZone("America/Los_Angeles")` and expects `"America/Los_Angeles"`. However, this is not a valid `NormalizedCustomID`.

Start with the JSON-B specification's TimeZone serialization requirement and the referenced tck/src/main/java/jakarta/json/bind/tck/defaultmapping/dates/DatesMappingTest.java testLongTimeZoneMapping method. Compare the stated NormalizedCustomID rule with the test's America/Los_Angeles expectation; done means the specification and test agree on valid serialization behavior.

Written by the indexing model from the issue text.