Reduce sizeof(TemplateArgument) from 32 to 24.

No intended functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@188959 91177308-0d34-0410-b5e6-96231b3b80d8
DebugInfo: Require only the declaration of types only used as parameter and return types

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@188962 91177308-0d34-0410-b5e6-96231b3b80d8