RFR: 8340830: Console.readLine() and Console.printf() are mutually blocking [v2]

[Naoto Sato]

> Fixing an issue in Console where write is blocked if other thread is waiting to read, which is caused by unnecessary read/write locks. Removing those would solve the problem, as the read/write synchronization is performed at the StreamEn/Decoder level. One unrelated change is to refactor double-checked locking with LazyConstant.

Naoto Sato has updated the pull request incrementally with two additional commits since the last revision:

 - Made ProxyingConsole value-based, used anonymous class for LazyConstant
 - Refine exceptions

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/29493/files
  - new: https://git.openjdk.org/jdk/pull/29493/files/28297eae..4848c481

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29493&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29493&range=00-01

  Stats: 27 lines in 2 files changed: 15 ins; 8 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/29493.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29493/head:pull/29493

PR: https://git.openjdk.org/jdk/pull/29493