Move LLVM to /third_party.

Bug 28616401

Change-Id: Ia54134e6e1dc6b101c7f81d9047e9bcc9fab3061
Reviewed-on: https://swiftshader-review.googlesource.com/5311
Tested-by: Nicolas Capens <capn@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>
8385 files changed