various: Fix missing DumpModule with recent LLVM.

various: Fix missing DumpModule with recent LLVM.

Since LLVM revision 293359 DumpModule gets only implemented when
either a debug build or LLVM_ENABLE_DUMP is set.

This patch adds a direct replacement for the function for radv and
radeonsi, However, as I don't know a good place to put common LLVM
code for all three I inlined the implementation for LLVMPipe.

v2: Use the new code for LLVM 3.4+ instead of LLVM 5+ & fixed indentation

Signed-off-by: Bas Nieuwenhuizen <basni@google.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>