[llvm] [IntrinsicEmitter] Make AttributesMap bits adaptive (PR #157965)

[Elvin Wang via llvm-commits]

elvinw-intel wrote:

> Instead of a build option, can we determine the packing automatically and use the right number of bits? And move any unpacking code into the TableGen generated code?

made the bit packing adaptive and moved `Intrinsic::getFnAttributes` to emitter

https://github.com/llvm/llvm-project/pull/157965