Remove LLVM_HAS_VARIADIC_TEMPLATES and all the faux variadic workarounds guarded by it.

We no longer support compilers without variadic template support.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229324 91177308-0d34-0410-b5e6-96231b3b80d8
6 files changed