RFR: 8310330: HttpClient: debugging interestOps/readyOps could cause exceptions and smaller cleanup [v3]

[Daniel Fuchs]

> Please find here a change that makes sure that debugging interestOps/readyOps won't cause exceptions to be raised.
> The change also contains smaller cleanup: extracting ALPN contants to their own class, removing/adding newlines at end of files, avoiding long lines in some occasions, removing some unused imports, etc...

Daniel Fuchs has updated the pull request incrementally with one additional commit since the last revision:

  Removed unused getFormat

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/14546/files
  - new: https://git.openjdk.org/jdk/pull/14546/files/a46fe48b..0f39f297

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=14546&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=14546&range=01-02

  Stats: 16 lines in 1 file changed: 0 ins; 16 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/14546.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14546/head:pull/14546

PR: https://git.openjdk.org/jdk/pull/14546