tests: Use CS_DISPATCH_BLOCKING instead of cycle

Some tests were using dispatch function in CS_DISPATCH_ALL mode
without poll/select on fd. This leads to busywait cycle, because
CS_DISPATCH_ALL masks CS_ERR_TRY_AGAIN error.

Simpliest solution is to use CS_DISPATCH_BLOCKING instead and remove
while cycle, because CS_DISPATCH_BLOCKING handles CS_ERR_TRY_AGAIN
correctly.

Signed-off-by: Jan Friesse <jfriesse@redhat.com>
Reviewed-by: Christine Caulfield <ccaulfie@redhat.com>