I found a regression between JDK 20+26 and JDK 20+30.
Before, these test work fine, after they fail like:
```
Couldn't initialize readline (java.lang.UnsupportedOperationException)
from org.truffleruby.stdlib.readline.ConsoleHolder.<init>(ConsoleHolder.java:142)
from org.truffleruby.stdlib.readline.ConsoleHolder.create(ConsoleHolder.java:89)
from org.truffleruby.RubyContext.getConsoleHolder(RubyContext.java:677)
from org.truffleruby.stdlib.readline.ReadlineNodes$BasicWordBreakCharactersNode.basicWordBreakCharacters(ReadlineNodes.java:69)
from org.truffleruby.stdlib.readline.ReadlineNodesFactory$BasicWordBreakCharactersNodeFactory$BasicWordBreakCharactersNodeGen.execute(ReadlineNodesFactory.java:105)
from org.truffleruby.language.RubyCoreMethodRootNode.execute(RubyCoreMethodRootNode.java:58)
Caused by:
Not a tty (java.io.IOException)
from org.graalvm.shadowed.org.jline.terminal.impl.ExecPty.current(ExecPty.java:44)
from org.truffleruby.stdlib.readline.ConsoleHolder.<init>(ConsoleHolder.java:127)
from org.truffleruby.stdlib.readline.ConsoleHolder.create(ConsoleHolder.java:89)
from org.truffleruby.RubyContext.getConsoleHolder(RubyContext.java:677)
from org.truffleruby.stdlib.readline.ReadlineNodes$BasicWordBreakCharactersNode.basicWordBreakCharacters(ReadlineNodes.java:69)
from org.truffleruby.stdlib.readline.ReadlineNodesFactory$BasicWordBreakCharactersNodeFactory$BasicWordBreakCharactersNodeGen.execute(ReadlineNodesFactory.java:105)
from org.truffleruby.language.RubyCoreMethodRootNode.execute(RubyCoreMethodRootNode.java:58)
Caused by:
Error executing 'tty': not a tty (java.io.IOException)
from org.graalvm.shadowed.org.jline.utils.ExecHelper.exec(ExecHelper.java:42)
from org.graalvm.shadowed.org.jline.terminal.impl.ExecPty.current(ExecPty.java:41)
from org.truffleruby.stdlib.readline.ConsoleHolder.<init>(ConsoleHolder.java:127)
from org.truffleruby.stdlib.readline.ConsoleHolder.create(ConsoleHolder.java:89)
from org.truffleruby.RubyContext.getConsoleHolder(RubyContext.java:677)
from org.truffleruby.stdlib.readline.ReadlineNodes$BasicWordBreakCharactersNode.basicWordBreakCharacters(ReadlineNodes.java:69)
from org.truffleruby.stdlib.readline.ReadlineNodesFactory$BasicWordBreakCharactersNodeFactory$BasicWordBreakCharactersNodeGen.execute(ReadlineNodesFactory.java:105)
from org.truffleruby.language.RubyCoreMethodRootNode.execute(RubyCoreMethodRootNode.java:58)
```

I would guess it's related to the recent addition of the internal JLine.

That error seems to mean the `tty` command had output `not a tty`.
Locally on linux-amd64, I get that output when stdin is /dev/null: `tty </dev/null`, but not if stdout and/or stderr are redirected (with original stdin).

I'm not sure how but it seems the new internal JLine messes up existing usages of JLine.
Maybe there can only be a single system terminal, or there is some side effect of changing stdin/stdout/stderr when calling `System.console() != null` (to find out if a TTY)?

Given the various issues with the internal JLine (e.g. JDK-8299689),
maybe it is worth reconsidering whether it's a good idea to add an internal copy of JLine in the JDK?

You can reproduce with the instructions to build TruffleRuby at https://github.com/oracle/truffleruby/blob/master/doc/contributor/workflow.md
And then:
```
bin/jt test spec/ruby/library/readline
```

This works fine on JDK 20+26, but fails on JDK 20+30.

It happens on at least linux-amd64, darwin-amd64 and darwin-aarch64.