REPL must not re-execute previously entered code
REPL must not re-execute previously entered code

A potential fix for RT#128973 would've led to all of previously
entered code to be stored in a variable and executed over and over,
for each new line of input. This test can now catch such regressions.

bitrauser/roast,zostay/roast,dogbert17/roast,bitrauser/roast,zostay/roast,perl6/roast,dogbert17/roast,zostay/roast