uselistorder: -mllvm -preserve-ll-use-list-order => -emit-llvm-uselists

Follow up to r234962, start respecting `-emit-llvm-uselists even for
LLVM assembly.  Note that the driver never passes this flag; this is
just a interface convenience/consistency for those using `-cc1`
directly.  This required LLVM r234969 (and predecessors).

llvm-svn: 234970