Revert "[VPlan] Move predication to VPlanTransform (NFC). (#128420)"
This reverts commit b263c08e1a0b54a871915930aa9a1a6ba205b099.
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