[llvm] [NFC][TableGen] Drop OperandInfo::addField/fields() wrappers and use OperandInfo::Fields instead (PR #195489)

[Prerona Chaudhuri via llvm-commits]

pchaudhuri-nv wrote:

The build bot ran into some issues - but they all seem to be unrelated to my change. All the error messages point to infrastructure issues. What should be done in such cases ?

https://github.com/llvm/llvm-project/pull/195489