[llvm] [LLVM][TableGen] Parameterize NumToSkip in DecoderEmitter (PR #135882)

[Florian Hahn via llvm-commits]

fhahn wrote:

It looks like this is triggering an assertion when building LLVM:

```
ssertion failed: (DestIdx > FixupIdx + NumToSkipSizeInBytes && "Expecting a forward jump in the decoding table"), function patchNumToSkip, file DecoderEmitter.cpp, line 151.
```

https://github.com/llvm/llvm-project/pull/135882