Port RFC2544.BackToBackFrames test to vsperf

Port RFC2544.BackToBackFrames test to vsperf

Add RFC2544.BackToBackFrames test and fix pylint errors.
Remove irrelevant values of back to back test results.

JIRA: VSPERF-46
Change-Id: I7a0dfd9494b509c3be7bffc0678228838d3059a1
Signed-off-by: Dino Simeon Madarang <dino.simeonx.madarang@intel.com>
Reviewed-by: Billy O Mahony <billy.o.mahony@intel.com>
Reviewed-by: Meghan Halton <meghan.halton@intel.com>
Reviewed-by: Maryam Tahhan <maryam.tahhan@intel.com>
Reviewed-by: Radek Zetik <radekx.zetik@intel.com>
Reviewed-by: Martin Klozik<martinx.klozik@intel.com>
Reviewed-by: Eugene Snider <Eugene.Snider@huawei.com>
Reviewed-by: Gurpreet Singh <gurpreet.singh@spirent.com>
Reviewed-by: Tv Rao <tv.rao@freescale.com>