fixes#154407
In HLSL the GVNPass was adding a phi node on
a target extention type.
https://hlsl.godbolt.org/z/sc14YenEe
This is something we cleaned up in a past PR
(https://github.com/llvm/llvm-project/pull/154620) by introducing
`isTokenLikeTy`. In the case of the GVN pass the target extention type
was still making its way through. This change makes it so if we see this
type we don't do PRE.
49fcfaa15a