L1TGlobalProducer: migrate to stream module (81x)

[fwyzard]

re-submission of #14352 after fixing a non-threadsafe construct

[fwyzard]

please test

[fwyzard]

@rekovic @mulhearn could you have a look ?

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/12950/console

[cmsbuild]

A new Pull Request was created by @fwyzard (Andrea Bocci) for CMSSW_8_1_X.

It involves the following packages:

L1Trigger/L1TGlobal

@cmsbuild, @rekovic, @mulhearn, @davidlange6 can you please review it and eventually sign? Thanks.
@Martin-Grunewald this is something you requested to watch as well.
@slava77, @Degano, @smuzaffar you are the release manager for this.

cms-bot commands are list here #13028

[cmsbuild]

+1
Tested at: 64a8baa
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-14476/12950/summary.html

The following merge commits were also included on top of IB + this PR after doing git cms-merge-topic:
08a43c3
60b365b
d89f2c1
b7e7db3
5e93ffa
You can see more details here:
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-14476/12950/git-log-recent-commits
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-14476/12950/git-merge-result

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-14476/12950/summary.html

[rekovic]

L1T unit tests passed

+1

[rekovic]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_8_1_X IBs after it passes the integration tests. This pull request requires discussion in the ORP meeting before it's merged. @slava77, @davidlange6, @Degano, @smuzaffar