RFR: 8305457: Implement java.io.IO [v12]

[Pavel Rappo]

> Please review this PR which introduces the `java.io.IO` top-level class and three methods to `java.io.Console` for [Implicitly Declared Classes and Instance Main Methods (Third Preview)].
> 
> This PR has been obtained as `git merge --squash` of a now obsolete [draft PR].
> 
> [Implicitly Declared Classes and Instance Main Methods (Third Preview)]: https://bugs.openjdk.org/browse/JDK-8323335
> [draft PR]: https://github.com/openjdk/jdk/pull/18921

Pavel Rappo has updated the pull request incrementally with one additional commit since the last revision:

  Force reasonable terminal size
  
  JLine outputs unexpected stuff if the terminal isn't dumb and small,
  such as that of our CI machines:
  
      if (newLines.size() > displaySize && !isTerminalDumb()) {
          StringBuilder sb = new StringBuilder(">....");
  
  This causes the IO test to fail with timeout, because the expected
  prompt is never matched. To avoid that, we reasonably size the
  terminal.

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/19112/files
  - new: https://git.openjdk.org/jdk/pull/19112/files/719560f6..e252c5d8

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19112&range=11
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19112&range=10-11

  Stats: 8 lines in 2 files changed: 1 ins; 6 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/19112.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19112/head:pull/19112

PR: https://git.openjdk.org/jdk/pull/19112