[llvm] [LowerSwitch] Don't let pass manager handle the dependency (PR #68662)

[Arthur Eubanks via llvm-commits]

https://github.com/aeubanks commented:

I didn't understand that this saves a pass run, this lgtm then

(also I thought I already sent out these comments, sorry for the delay)

https://github.com/llvm/llvm-project/pull/68662