High Granularity Optimization

speed up various critical packages by using Ofast option
as described in
https://twiki.cern.ch/twiki/bin/view/CMS/HighGranularityCMSSWOptimization
and discussed in April in some Reco/Offline meeting

a small regression is observed in primaryVertices (greatly mitigated w/r/t the very first attempts).
This "cascades" in general tracks and conversions as primaryVertices are used in the seeding
checking against "0" to protect against a divBy0 looks pretty legal to me.
see above about redundancy of messages in case of assert