Fix stdin/out for repl launched by SBT
Fix stdin/out for repl launched by SBT

Launching the repl with: `runMain dotty.tools.dotc.repl.Main` is now
working correctly

sjrd/dotty,lampepfl/dotty,dotty-staging/dotty,sjrd/dotty,sjrd/dotty,som-snytt/dotty,som-snytt/dotty,dotty-staging/dotty,som-snytt/dotty,som-snytt/dotty,lampepfl/dotty,dotty-staging/dotty,sjrd/dotty,lampepfl/dotty,dotty-staging/dotty,lampepfl/dotty,lampepfl/dotty,dotty-staging/dotty,som-snytt/dotty,sjrd/dotty