[NFC][DirectX] Clean-up of DXIL.td (#124005)

- Runs clang-format on `DXIL.td`
Note: this does not include the suggested formatting changes to `defset
list<DXILOpClasses> OpClasses` as it does not enforce the formatting
that is primarily used elsewhere
- Reorders currently defined `DXIL` ops by opcode in ascending order to
be consistent with other definitions

This is a small cleanup moved to be separate from
[#115912](#115912) for
reviewability.

Author: inbelic