[14.2.X] Backport multi-arch chanegs from 15.0.X

[smuzaffar]

This includes

• Fix for python import issues during patch release build phase (Fix for importing ClassesDefXmlUtils cmssw#46919) patch release build fix: use realpath for import python module #9574
• Copying of rootmap files before running edmCheckClassVersion ([BuildRule] Copy rootmap to lib product store #9568)
• Use correct object for alpaka serial backend for additional micro-arch (Generate compile rules for addtional microarch for alpaka serial backend #9571)

[smuzaffar]

test parameters:

• full_cmssw = true

[smuzaffar]

please test

[cmsbuild]

A new Pull Request was created by @smuzaffar for branch IB/CMSSW_14_2_X/master.

@aandvalenzuela, @iarspider, @smuzaffar can you please review it and eventually sign? Thanks.
@antoniovilela, @mandrenguyen, @rappoccio, @sextonkennedy you are the release manager for this.
cms-bot commands are listed here

[cmsbuild]

cms-bot internal usage

[cmsbuild]

+1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-933535/43404/summary.html
COMMIT: cacffc0
CMSSW: CMSSW_14_2_X_2024-12-11-2300/el8_amd64_gcc12
User test area: For local testing, you can use /cvmfs/cms-ci.cern.ch/week1/cms-sw/cmsdist/9572/43404/install.sh to create a dev area with all the needed externals and cmssw changes.

Comparison Summary

Summary:

• You potentially removed 148 lines from the logs
• Reco comparison results: 26 differences found in the comparisons
• DQMHistoTests: Total files compared: 46
• DQMHistoTests: Total histograms compared: 3483722
• DQMHistoTests: Total failures: 1538
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3482164
• DQMHistoTests: Total skipped: 20
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 45 files compared)
• Checked 202 log files, 172 edm output root files, 46 DQM output files
• TriggerResults: found differences in 1 / 44 workflows

[smuzaffar]

+externals

Lets get this in for 14.2.X IB

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next IB/CMSSW_14_2_X/master IBs (tests are also fine). This pull request will now be reviewed by the release team before it's merged. @mandrenguyen, @sextonkennedy, @antoniovilela, @rappoccio (and backports should be raised in the release meeting by the corresponding L2)