[CodeGen] Generalize MachineFunctionProperties::print comma handling.

This is only used for debug prints, but the previous hardcoded ", "
caused it to be printed unnecessarily when OnlySet, and is annoying
when adding new properties.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@277465 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed