[llvm] [TableGen] Emit Debug code for dynamic bits(eg: instruction operands) in DecoderEmitter (PR #194699)

[Sam Elliott via llvm-commits]

lenary wrote:

> IIUC, this already exists on TOT right ? I was trying to see if our decoder can print the bits for which the decoding failed. Generally operands have these "dynamic bits" i.e some of the bits are set by the appropriate encoder functions which are invoked at run time..
> 
> May I know what were you trying to convey ?

Yeah, sorry, you're right that the per-instruction decoder is logged after the fact on `main` right now.

Thanks for investigating why X86 doesn't show any overhead.

https://github.com/llvm/llvm-project/pull/194699