PR19278: Align ASTTemplateArgumentListInfo to match its following dynamic array
of TemplateArgumentLocs. 'uint64_t' has higher alignment requirements than a
pointer on some platforms.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@205068 91177308-0d34-0410-b5e6-96231b3b80d8