[jdk13u-dev] RFR: 8236859: WebSocket over authenticating proxy fails with NPE

[Larry-N]

Backport fix for bug 8236859
+ small correction  cache.store() calling because of method signature difference from 16 to 13 jdk. 
File: AuthenticationFilter.java

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Commit messages:
 - Backport c6da6681d418928c65cff6b1240e6b5d6bc5199b

Changes: https://git.openjdk.java.net/jdk13u-dev/pull/53/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk13u-dev&pr=53&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8236859
  Stats: 948 lines in 12 files changed: 909 ins; 5 del; 34 mod
  Patch: https://git.openjdk.java.net/jdk13u-dev/pull/53.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk13u-dev pull/53/head:pull/53

PR: https://git.openjdk.java.net/jdk13u-dev/pull/53