Add burst support (#149)

Netperf's TCP_RR supports burst mode which allows netperf process
to send multiple transactions in flight at one time.

When run with just a single instance of netperf, increasing the
burst size can determine the maximum number of transactions per
second which can be serviced by a single process

Running burst with concurrent netperf tests is like
“aggregate of aggregates” and helps in determine the maximum
number of transactions per second on the node.

By default, TCP_RR uses burst mode of one transaction in flight
at one time.

Burst mode is similar to queue depth in other testing tools.

Burst is added to results reporting to differentiate tests
run with different burst configuration.

As "-m" is TCP_STREAM specific option, it is configured for
STREAM testing only. "-r" option is used to specify packet size
for netperf TCP_RR testing.

Signed-off-by: venkataanil <anil.venkata@enovance.com>