merge from trunk r44651 and 48325

 - 44651:  problem in combine when some  have bins with zero errors
 - 48325: Coverity fix for a wrong check for consistent binning in Combine()


git-svn-id: https://root.cern.ch/svn/root/branches/v5-34-00-patches@48329 27541ba8-7e3a-0410-8455-c3a389f83636
merge from trunk r48328 (fix bug using option W from TGraphErrros)


git-svn-id: https://root.cern.ch/svn/root/branches/v5-34-00-patches@48330 27541ba8-7e3a-0410-8455-c3a389f83636