This PR does
1. Support the case where $c holding a mma layout, this should be useful
in forloop in k-axis in GEMM
2. Fix the `unrealized_conversion_cast` in ConvertLayout[shared->dot_op]
Known issue
1. There is some IO conflict in GEMM with a k-forloop, it is temporarily
solved by [adding a
barrier](https://github.com/openai/triton/pull/798/files#diff-8a9a5a7f4a025fb1299af29d190d5626bd9000406d3ea47c49679272d3d6abe9R3028)
in dot conversion, but we are still working on it, will get a more
generic fix for it in the following PR.
2. The parallel pass will result in a buggy instruction result type
```mlir
%1049 = llvm.inline_asm has_side_effects asm_dialect = att operand_attrs = [] "cp.async.commit_group ;", "" : () -> !llvm.void
%1050 = builtin.unrealized_conversion_cast %1049 : !llvm.void to !llvm.ptr<f16, 3>
```
So we temporarily disable it.
4dc2396ca0