tipc: Remove code to emulate loss of broadcast messages

Eliminates optional code used to test TIPC's ability to recover
from lost broadcast messages. This code duplicates functionality
already provided by the network stack's QoS option "network emulator".

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>