fix handling of air/iron in DD4hep MF construction

[namapane]

PR description:

This is a backport of #33593. It is needed to fix muon reco with DD4hep.

[cmsbuild]

A new Pull Request was created by @namapane (Nicola Amapane) for CMSSW_11_3_X.

It involves the following packages:

MagneticField/GeomBuilder

@perrotta, @jpata, @cmsbuild, @slava77 can you please review it and eventually sign? Thanks.
@silviodonato, @dpiparo, @qliphy you are the release manager for this.

cms-bot commands are listed here

• Backported from fix handling of air/iron in DD4hep MF construction #33593

[ianna]

please test

[cmsbuild]

+1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-9402bb/14759/summary.html
COMMIT: e0bd8d2
CMSSW: CMSSW_11_3_X_2021-04-30-1100/slc7_amd64_gcc900
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week0/cms-sw/cmssw/33594/14759/install.sh to create a dev area with all the needed externals and cmssw changes.

Comparison Summary

Summary:

• No significant changes to the logs found
• Reco comparison results: 84 differences found in the comparisons
• DQMHistoTests: Total files compared: 38
• DQMHistoTests: Total histograms compared: 2877046
• DQMHistoTests: Total failures: 1984
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 2875040
• DQMHistoTests: Total skipped: 22
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 37 files compared)
• Checked 160 log files, 37 edm output root files, 38 DQM output files
• TriggerResults: no differences found

[slava77]

type bugfix

[slava77]

backport of #33593

[slava77]

reco comparisons are as expected, in the DD4HEP workflow 11634.911 (and we are in luck that everything else in this workflow was reproducible)
this and similar plots show that muon matching is now correct (the residual is smaller)

[slava77]

+reconstruction

for #33594 e0bd8d2

• code changes are in line with the PR description
• the backport is correct (code changes are the same as in the master/12_0_X variant fix handling of air/iron in DD4hep MF construction #33593
• jenkins tests pass and comparisons with the baseline show differences only in DD4HEP workflow, as expected fix handling of air/iron in DD4hep MF construction #33594 (comment)

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_11_3_X IBs (tests are also fine) and once validation in the development release cycle CMSSW_12_0_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)

[qliphy]

+1