RFR: JDK-8273146: Start of release updates for JDK 19 [v2]

[Joe Darcy]

> The time to get JDK 19 underway draws nigh, please review this usual set of start-of-release updates, including CSRs for the javac and javax.lang.model updates:
> 
> JDK-8277512: Add SourceVersion.RELEASE_19
> https://bugs.openjdk.java.net/browse/JDK-8277512
> 
> JDK-8277514: Add source 19 and target 19 to javac
> https://bugs.openjdk.java.net/browse/JDK-8277514
> 
> Clean local tier 1 test runs for langtools, jdk, and hotspot.

Joe Darcy has updated the pull request incrementally with one additional commit since the last revision:

  Respond to review feedback.

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/6493/files
  - new: https://git.openjdk.java.net/jdk/pull/6493/files/5052cd90..4da056ab

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=6493&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=6493&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6493.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6493/head:pull/6493

PR: https://git.openjdk.java.net/jdk/pull/6493