Fixes#1369 (Prefixing commands with a space is not working)
The regression was introduced by this commit:
68bcca22a0
Since then the main logic for the REPL was hugely refactored. This
refactoring morphed the error into this commit:
e020f8cecd
Sorry about this hacky solution.
Prior to this change, when auto_indent was set to true for some tests,
the green dots would be cleared half-way through.
We should probably re-consider these options, but it seems useful to
explicitly disable ANSI code rewriting during specs while leaving
indentation mutating read lines (before this change, there was a bug
in REPL that did not manifest because auto_indent was false).