[llvm] [VPlan] Move predication to VPlanTransform (NFC). (PR #128420)

[Florian Hahn via llvm-commits]

fhahn wrote:

Reverted for now in 793bb6b257fa4d9f4af169a4366cab3da01f2e1f as it   looks like this triggers a crash in one of the Fortran tests. Reverting while I investigate
        https://lab.llvm.org/buildbot/\#/builders/41/builds/6825

https://github.com/llvm/llvm-project/pull/128420