RFR: 8332161: Test restoring echo in the Console implementation (java.base) [v2]

[Naoto Sato]

> This test intends to verify the behavior of JdkConsole for the java.base module, wrt restoring the echo. The test assumes the internal methods that sets/gets the echo status of the platform.

Naoto Sato has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains five additional commits since the last revision:

 - leftover typo
 - get/setEcho() -> echo()
 - Merge branch 'JDK-8332084-restoreEcho-readLock' into JDK-8332161-restoreEcho-Test
 - Merge branch 'JDK-8332084-restoreEcho-readLock' into JDK-8332161-restoreEcho-Test
 - initial commit

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/19315/files
  - new: https://git.openjdk.org/jdk/pull/19315/files/58151807..ad4a4e47

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19315&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19315&range=00-01

  Stats: 34602 lines in 391 files changed: 29274 ins; 4096 del; 1232 mod
  Patch: https://git.openjdk.org/jdk/pull/19315.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19315/head:pull/19315

PR: https://git.openjdk.org/jdk/pull/19315