MINOR: cli: Remove useless loop on commands to find unescaped semi-colon

MINOR: cli: Remove useless loop on commands to find unescaped semi-colon

This loop was added to detect pipelined commands when only co_getline() was
used to get commands. Now, co_getdelim() is used and the semi-colon is also
considered as a command delimiter.

As side effet, the last semi-colon, if any, is no longer replaced by a
newline. Thus, we must take care to adapt the test to detect partial
commands.