SWT CI uses wrong build as reference for warnings #1648
Description
Currently CI builds fail stating there are new issues even if they fix issues (example: #1620) or if its just a new master build.
The root reason is that the reference build used is wrong:
master 830 should have 829 as reference but took 826
see
https://ci.eclipse.org/releng/job/eclipse.platform.swt/job/master/
The reference is configured in Jenkinsfile,
one can see how it is configured in other projects that do not have this problem like:
https://github.com/eclipse-jdt/eclipse.jdt.core/blob/abe441acccc0955f7a7cb3bd38b789fe1870adc0/Jenkinsfile#L48