[llvm] [TableGen][DecoderEmitter] Add extractBits() overloads (PR #159405)

[Sergei Barannikov via llvm-commits]

s-barannikov wrote:

Sorry, I can no longer reproduce the announced speedup. There is a difference, but it is small.
Either I had some unstaged changes that made the difference, or I just compared different things. :man_facepalming: The signal was stable though :)


https://github.com/llvm/llvm-project/pull/159405