[jdk17u] RFR: 8276774: Cookie stored in CookieHandler not sent if user headers contain cookie

[Evan Whelan]

Hi,

Please review my clean backport of JDK-8276774 

This fix passed all CI testing and fixes a regression introduced in JDK-8213189

Kind regards,
Evan

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

Commit messages:
 - 8276774: Cookie stored in CookieHandler not sent if user headers contain cookie

Changes: https://git.openjdk.java.net/jdk17u/pull/300/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk17u&pr=300&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8276774
  Stats: 82 lines in 4 files changed: 35 ins; 18 del; 29 mod
  Patch: https://git.openjdk.java.net/jdk17u/pull/300.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk17u pull/300/head:pull/300

PR: https://git.openjdk.java.net/jdk17u/pull/300