Update L1T GT/Calo/GMT unpackers to have non-null product instances

[mulhearn]

The unpacker code for L1T GT/Calo/GMT unpackers are updated to set the product instance to the object type.

This allows downstream HLT code to use edm::View in order to access the four-vectors of L1T objects.

The L1T downstream code required updates to adapt to this change, which has been completed, for all but some test code in L1Trigger/L1TGlobal which can be adapted separately.

[cmsbuild]

A new Pull Request was created by @mulhearn for CMSSW_8_0_X.

It involves the following packages:

DQM/L1TMonitor
EventFilter/L1TRawToDigi
HLTrigger/HLTfilters
L1Trigger/Configuration
L1Trigger/HardwareValidation
L1Trigger/L1TCalorimeter
L1Trigger/L1TCommon
L1Trigger/L1TGlobal
L1Trigger/L1TNtuples

@perrotta, @cmsbuild, @Martin-Grunewald, @deguio, @fwyzard, @vanbesien, @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

[mulhearn]

I'm not signing this one until I better understand where it should go (i.e. into MWGR#3).

[mulhearn]

please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/11666/console

[cmsbuild]

+1
Tested at: f46d959
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-13547/11666/summary.html

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-13547/11666/summary.html

[Martin-Grunewald]

+1

[mulhearn]

+1