RFR: 8325361: Make sun.net.www.MessageHeader final [v2]

[Korov]

> Make sun.net.www.MessageHeader final, and replace C-style array type declaration with Java-style array declaration.

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

  remove @SuppressWarnings("this-escape")

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Changes:
  - all: https://git.openjdk.org/jdk/pull/17997/files
  - new: https://git.openjdk.org/jdk/pull/17997/files/40c7f899..187df0fe

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17997&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17997&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/17997.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17997/head:pull/17997

PR: https://git.openjdk.org/jdk/pull/17997