[llvm] [TableGen][DecoderEmitter] Use KnownBits for filters/encodings (NFCI) (PR #154691)

[Sergei Barannikov via llvm-commits]

s-barannikov wrote:

I can split this PR into two it is too much for one (one for each commit).


https://github.com/llvm/llvm-project/pull/154691