Fix cleanup of timestamp cache on the JobSubmitter

Last patch has a bug when cleaning up the memory cache on
workflow timestamps, fix this here.
Fix bug in smart lumi splitter

It failed if the conditions aligned and it was trying to process
a too-big single-lumi file.

Add unit-test that fails without the fix
add merged flag for framework job report
Merge pull request #4334 from dballesteros7/fixSmartLumiSplitter

Fix bug in smart lumi splitter
Merge pull request #4335 from dballesteros7/fixLastFix

Fix cleanup of timestamp cache on the JobSubmitter
Merge pull request #4336 from ticoann/add_merged_flag_frwj

add merged flag for framework job report