Make use of IB RelVal stats while running CMSSW Pull Request tests

[smuzaffar]

Make use of IB RelVals stats (memory usage, cpu usage etc) for running runTheMatrix for PR tests in parallel.

[cmsbuild]

A new Issue was created by @smuzaffar Malik Shahzad Muzaffar.

@davidlange6, @Dr15Jones, @smuzaffar, @fabiocos, @kpedro88 can you please review it and eventually sign/assign? Thanks.

cms-bot commands are listed here

[fabiocos]

@smuzaffar related to this, now that we are keeping the performance info for PR tests in JobReport.xml, it would be useful to add them also for baseline results, so as to make comparison (although to be taken with care). Which are the scripts to be touched? I see the old standard option mentioned in https://github.com/cms-sw/cms-bot/blob/master/RelValArgs.py#L26 , so it could be probably updated there only, am I correct?