RFR: 7105350: HttpExchange's attributes are the same as HttpContext's attributes [v15]

[Josiah Noel]

> Now ExchangeImpl will default to having a separate attribute map for the request duration.

Josiah Noel has updated the pull request incrementally with two additional commits since the last revision:

 - Update ExchangeAttributeTest.java
 - pr comments

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Changes:
  - all: https://git.openjdk.org/jdk/pull/27652/files
  - new: https://git.openjdk.org/jdk/pull/27652/files/d250e34d..3e9a247e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27652&range=14
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27652&range=13-14

  Stats: 138 lines in 3 files changed: 13 ins; 118 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/27652.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27652/head:pull/27652

PR: https://git.openjdk.org/jdk/pull/27652