[12_0_X] Backport the fix on the workflow 537 and the mergeLHE.py script#34861

cmsbuild merged 2 commits intocms-sw:CMSSW_12_0_Xcms-sw/cmssw:CMSSW_12_0_Xfrom

colizz:dev-120X-fixWorkflow537AndFixMergeLHEcolizz/cmssw:dev-120X-fixWorkflow537AndFixMergeLHECopy head branch name to clipboard