Speed startup by asynchronous initialization of ReplIO

[JaroslavTulach]

Investigation of

• 16% startup regression after including GraalPy #8553 (comment)

revealed that another reason for slowing the startup by 16% (while measurements were off) is replacement of DumbTerminal:

by proper and more capable

org.jline.terminal.impl.jna.JnaTerminalProvider.sysTerminal()

As the terminal isn't going to needed for next 1 or 2 seconds, let's defer its initialization into own (low priority) Thread.

[JaroslavTulach]

By initializing in own thread, we can eliminate Thread.currentThread().setContextClassLoader(prevClassLoader) - as the thread will die out after performing initialization.

[JaroslavTulach]

When at it we could rewrite ReplIO (and maybe also Repl) into Java.

[jdunkerley]

Closed as duplicate of #8688