RFR: 8332161: Test restoring echo in the Console implementation (java.base) [v4]

[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 20 additional commits since the last revision:

 - Merge branch 'JDK-8332084-restoreEcho-readLock' into JDK-8332161-restoreEcho-Test
 - Added comment for restoreEchoLock
 - fixing typo
 - Merge branch 'JDK-8332084-restoreEcho-readLock' into JDK-8332161-restoreEcho-Test
 - Merge branch 'master' into JDK-8332084-restoreEcho-readLock
 - leftover typo
 - get/setEcho() -> echo()
 - Merge branch 'JDK-8332084-restoreEcho-readLock' into JDK-8332161-restoreEcho-Test
 - Used a dedicate lock for restoreEcho
 - Merge branch 'JDK-8332084-restoreEcho-readLock' into JDK-8332161-restoreEcho-Test
 - ... and 10 more: https://git.openjdk.org/jdk/compare/8d2a0559...7311487f

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/19315/files
  - new: https://git.openjdk.org/jdk/pull/19315/files/1cd88c61..7311487f

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19315&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19315&range=02-03

  Stats: 1 line in 1 file changed: 1 ins; 0 del; 0 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