R600/SI: Fix insertelement with dynamic indices.

This didn't work for any integer vectors, and didn't
work with some sizes of float vectors. This should now
work with all sizes of float and i32 vectors.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200619 91177308-0d34-0410-b5e6-96231b3b80d8
Add some xfailed R600 tests for 64-bit private accesses.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200620 91177308-0d34-0410-b5e6-96231b3b80d8