RFR: 8247403: JShell: No custom input (e.g. from GUI) possible with JavaShellToolBuilder

[Jan Lahoda]

Basically, JShell's ConsoleIOContext always uses the JLine's default terminal, which uses System.in, or equivalent, for input. But, if the JShell tool has been created using JavaShellToolBuilder, a different input might have been provided. The proposed solution is to use a different JLine's terminal in this case, based on the provided input.

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Commit messages:
 - 8247403: JShell: No custom input (e.g. from GUI) possible with JavaShellToolBuilder

Changes: https://git.openjdk.java.net/jdk/pull/2509/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2509&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8247403
  Stats: 81 lines in 2 files changed: 74 ins; 0 del; 7 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2509.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2509/head:pull/2509

PR: https://git.openjdk.java.net/jdk/pull/2509