protect SiStripTkMaps in case of empty inputs, also test for it in unit tests

[mmusich]

PR description:

#45952 exposed a fragility in SiStripTkMaps when there is no actual input in it. The failing unit test was fixed via #45954, but the possibility to generate a segmentation fault when not filling the map remains. This is fixed in this PR.
To demonstrate the viability I add a section to the catch2 unit tests for this use case.

PR validation:

scram b runtests runs fine.

If this PR is a backport please specify the original PR and why you need to backport that PR. If this PR will be backported please specify to which release cycle the backport is meant for:

N/A

[cmsbuild]

cms-bot internal usage

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-45966/41723

[cmsbuild]

A new Pull Request was created by @mmusich for master.

It involves the following packages:

• DQM/TrackerRemapper (dqm)

@antoniovagnerini, @cmsbuild, @nothingface0, @rvenditti, @syuvivida, @tjavaid can you please review it and eventually sign? Thanks.
@fioriNTU, @idebruyn, @jandrea, @threus this is something you requested to watch as well.
@antoniovilela, @mandrenguyen, @rappoccio, @sextonkennedy you are the release manager for this.

cms-bot commands are listed here

[mmusich]

@cmsbuild, please test

[cmsbuild]

+1

Size: This PR adds an extra 20KB to repository
Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-78f2b5/41434/summary.html
COMMIT: fab1750
CMSSW: CMSSW_14_2_X_2024-09-09-2300/el8_amd64_gcc12
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week0/cms-sw/cmssw/45966/41434/install.sh to create a dev area with all the needed externals and cmssw changes.

Comparison Summary

Summary:

• You potentially added 3 lines to the logs
• Reco comparison results: 77 differences found in the comparisons
• DQMHistoTests: Total files compared: 44
• DQMHistoTests: Total histograms compared: 3331158
• DQMHistoTests: Total failures: 4592
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3326546
• DQMHistoTests: Total skipped: 20
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 43 files compared)
• Checked 193 log files, 163 edm output root files, 44 DQM output files
• TriggerResults: no differences found

[antoniovagnerini]

+1

• spurious differences seen from unstable WF 12834.7 (open issue spurious differences in outputs of Run-3 wfs *.7 #39803 )

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next master IBs (tests are also fine). This pull request will now be reviewed by the release team before it's merged. @antoniovilela, @rappoccio, @mandrenguyen, @sextonkennedy (and backports should be raised in the release meeting by the corresponding L2)

[mandrenguyen]

+1