Use Die->addValue and DIEIntegerOne directly when we want to add
a flag. No functional change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191990 91177308-0d34-0410-b5e6-96231b3b80d8
Use addFlag to add the enum class attribute.

This has the side effect of using DW_FORM_flag_present on dwarf4 and above.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191991 91177308-0d34-0410-b5e6-96231b3b80d8