squashed fastsim decays for backport to C94x

[sbein]

This is a backport of LL FastSim exotic decay physics 31285 in the head to 94x.

[cmsbuild]

A new Pull Request was created by @sbein (Sam Bein) for CMSSW_9_4_X.

It involves the following packages:

FastSimulation/SimplifiedGeometryPropagator

@ssekmen, @lveldere, @civanch, @mdhildreth, @cmsbuild, @sbein can you please review it and eventually sign? Thanks.
@matt-komm this is something you requested to watch as well.
@silviodonato, @dpiparo, @qliphy you are the release manager for this.

cms-bot commands are listed here

• Backported from Solution for decay products of Long-lived exotic particles in FastSim  #31285

[sbein]

+1

[cmsbuild]

The tests are being triggered in jenkins.

• CMSSW_9_4_X_2020-09-20-0000/slc6_amd64_gcc630: https://cmssdt.cern.ch/jenkins/job/ib-run-pr-tests/9585/console Started: 2020/09/25 20:03

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_9_4_X IBs after it passes the integration tests and once validation in the development release cycle CMSSW_11_2_X is complete. This pull request will now be reviewed by the release team before it's merged. @silviodonato, @dpiparo, @qliphy (and backports should be raised in the release meeting by the corresponding L2)

[cmsbuild]

+1
Tested at: 2554565
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-d505f8/9585/summary.html
CMSSW: CMSSW_9_4_X_2020-09-20-0000
SCRAM_ARCH: slc6_amd64_gcc630

[cmsbuild]

Comparison job queued.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-d505f8/9585/summary.html

Comparison Summary:

• No significant changes to the logs found
• Reco comparison results: 0 differences found in the comparisons
• DQMHistoTests: Total files compared: 27
• DQMHistoTests: Total histograms compared: 2721493
• DQMHistoTests: Total failures: 114
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 2721217
• DQMHistoTests: Total skipped: 162
• DQMHistoTests: Total Missing objects: 0

[qliphy]

+1

[silviodonato]

backport of #31285