Makes '--comma-separated val1,val2' mean the same thing as
'--comma-separated=val1,val2' (that is, 'val1' and 'val2' are not lumped
together as 'val1,val2'). Also declutters the main loop a bit.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89463 91177308-0d34-0410-b5e6-96231b3b80d8