[llvm] [GlobalISel] Add boolean predicated legalization action methods. (PR #111287)

[via llvm-commits]

Him188 wrote:

Adding one more idea - I attempted to propose a predicate `hasFP16()` to be used in combination of `all`. So a typical usage looks like:

```cpp
.legalIf(all(hasFP16(), typeInSet(0, {v8s16, v4s16})))
```

Which sounds like @aemerson 's idea but does not require a new `AddIf`.

See
https://github.com/llvm/llvm-project/pull/104753#discussion_r1731827259


https://github.com/llvm/llvm-project/pull/111287