RFR: 8304927: Update java/net/httpclient/BasicAuthTest.java to check basic auth over HTTP/2

Mon Mar 27 10:00:17 UTC 2023

The BasicAuthTest only tests basic authentication with clear HTTP/1.1. 
This changes upgrades it to also test against TLS,  as well as HTTP/2.
The bulk of the fix is to move the implementation of a HttpBasicAuthFilter from DigestEchoServer.java to HttpServerAdapters. This makes it possible to enable basic auth in the HTTP/2 test server.

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Commit messages:
 - 8304927

Changes: https://git.openjdk.org/jdk/pull/13189/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13189&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8304927
  Stats: 402 lines in 3 files changed: 217 ins; 145 del; 40 mod
  Patch: https://git.openjdk.org/jdk/pull/13189.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13189/head:pull/13189

PR: https://git.openjdk.org/jdk/pull/13189