This PR is simply adding parameter-less `java.io.IO.{println(),readln()}`, with
the (hopefully) obvious semantics, plus the corresponding wiring to make those
work. This may become part of JEP 495:
https://openjdk.org/jeps/495
-------------
Commit messages:
- Adding support for IO.readln()
- 8342936: Enhance java.io.IO with parameter-less println()
Changes: https://git.openjdk.org/jdk/pull/21693/files
Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21693&range=00
Issue: https://bugs.openjdk.org/browse/JDK-8342936
Stats: 214 lines in 13 files changed: 197 ins; 8 del; 9 mod
Patch: https://git.openjdk.org/jdk/pull/21693.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/21693/head:pull/21693
PR: https://git.openjdk.org/jdk/pull/21693
