Fixed precedence order problem with FormulaEvaluator

[Dr15Jones]

Under certain conditions one of the evaluation nodes could be dropped because of a faulty precedence handling.
Unit tests were also extended to test this case.

[cmsbuild]

A new Pull Request was created by @Dr15Jones (Chris Jones) for CMSSW_9_0_X.

It involves the following packages:

CommonTools/Utils

@cmsbuild, @cvuosalo, @slava77, @monttj, @davidlange6 can you please review it and eventually sign? Thanks.
@makortel this is something you requested to watch as well.
@slava77, @smuzaffar you are the release manager for this.

cms-bot commands are listed here #13028

[Dr15Jones]

please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/16561/console

[slava77]

@blinkseb
please confirm that this PR solves the problem

@Dr15Jones we will need 80X and 81X versions of this

[cmsbuild]

+1
Tested at: 3b2658f
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-16733/16561/summary.html

[cmsbuild]

Comparison job queued.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-16733/16561/summary.html

[blinkseb]

@slava77 Applying 3b2658f on top of CMSSW 8.0.24 fix the issue, I now have exactly the same output from CMSSW than from ROOT!

Thanks a lot!

[slava77]

+1

for #16733 3b2658f

• fix to formula in JEC not yet released for standard workflows. Resolution is confirmed by @blinkseb
• jenkins tests pass and comparisons show no differences