Add support for building with Python 3
Add support for building with Python 3

LLDB supports Python 3 now.

Differential Revision: https://reviews.llvm.org/D64443

Patch from Christian Biesinger <cbiesinger@google.com>!

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@365692 91177308-0d34-0410-b5e6-96231b3b80d8

GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm