Implement LowerCall_64 for the SPARC v9 64-bit ABI.

There is still no support for byval arguments (which I don't think are
needed) and varargs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178993 91177308-0d34-0410-b5e6-96231b3b80d8