Redis used to crash with a call like the following:
EVAL "redis.call()" 0
Now the explicit check for at least one argument prevents the problem.
This commit fixes issue #655.
wait_for_condition is now used instead of the usual "after 1000" (that
is the way to sleep in Tcl). This should avoid to find the replica in
a state where it is loading the RDB in memory, returning -LOADING error.
This test used to fail when running the test over valgrind, due to the
added latencies.
A new primitive wait_for_condition was introduced in the scripting
engine that makes waiting for events simpler, so that it is simpler to
write tests that are more resistant to timing issues.
