Sudden prompt over a lengthy intrinsic in REPL

[marcgurevitx]

Currently in C++ REPL if one runs some lengthy intrinsic (eg exec "sleep 100", 101), after 60 seconds the REPL suddenly prompts for input. If one just presses Return, it continues to run and finishes the call.

The proposal is to eliminate the surprising prompt and to just continue working as long as it takes.