[TableGen] Change TGParser::SetValue to take an ArrayRef instead of std::vector reference. Use None in many places where a default constructed vector was being passed. NFC

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@256726 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed