[RF] Exclude categories from overlap checks in multi-range fits

[guitargeek]

This is necessary because some of the pdf observables can be categories,
e.g. in the case of the RooSimultaneous.

Since this problem was uncovered by a user when working with
RooSimultaneous, the reproducer of the original problem was turned into
a unit test in testRooSimultaneous.

Link to original forum post:
https://root-forum.cern.ch/t/roofit-failed-to-create-nll-for-simultaneous-pdfs-with-multiple-range-names/49363

Should be backported to the 6.26 branch.

[phsft-bot]

Starting build on ROOT-debian10-i386/cxx14, ROOT-performance-centos8-multicore/default, ROOT-ubuntu16/nortcxxmod, ROOT-ubuntu2004/soversion, mac1015/python3, mac11/cxx17, windows10/cxx14
How to customize builds

[phsft-bot]

Build failed on ROOT-ubuntu2004/soversion.
Running on root-ubuntu-2004-3.cern.ch:/home/sftnight/build/workspace/root-pullrequests-build
See console output.

Failing tests:

• projectroot.roofit.roofitcore.test.gtest_roofit_roofitcore_test_testRooSimultaneous

[phsft-bot]

Build failed on ROOT-performance-centos8-multicore/default.
Running on olbdw-01.cern.ch:/data/sftnight/workspace/root-pullrequests-build
See console output.

Failing tests:

• projectroot.roofit.roofitcore.test.gtest_roofit_roofitcore_test_testRooSimultaneous

[phsft-bot]

Build failed on mac11/cxx17.
Running on macphsft23.dyndns.cern.ch:/Users/sftnight/build/workspace/root-pullrequests-build
See console output.

Failing tests:

• projectroot.roofit.roofitcore.test.gtest_roofit_roofitcore_test_testRooSimultaneous

[lmoneta]

LGTM!
Thanks for the fix and great you have now added also a test for this!

[hahnjo]

The test projectroot.roofit.roofitcore.test.gtest_roofit_roofitcore_test_testRooSimultaneous has been failing on this PR and is now in all subsequent PRs!