RFR: 8304927: Update java/net/httpclient/BasicAuthTest.java to check basic auth over HTTP/2 [v2]

[Daniel Fuchs]

> 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.

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

  Added ca.count in exception message

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Changes:
  - all: https://git.openjdk.org/jdk/pull/13189/files
  - new: https://git.openjdk.org/jdk/pull/13189/files/446b1b48..968f1fb4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13189&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13189&range=00-01

  Stats: 9 lines in 1 file changed: 3 ins; 0 del; 6 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