[VPlan] Remove no-longer-needed EVL VPlan debug output tests. NFC (llvm#166158)

These VPlan debug output tests were added in
llvm#108351 and
llvm#110412, whenever we used to
convert regular widening recipes to VP intrinsics during EVL tail
folding.

Nowadays we don't convert these recipes so there's nothing really to be
gained from testing them. This removes the VPlan tests since an upcoming
patch slightly perturbs these VPlans and removing them seems easier than
manually going through and updating them all.

I've kept behind the LLVM IR/UTC counterparts in
`tail-folding-{cast,call}-intrinsics.ll`, since even though they also
aren't really testing anything useful at least they're easy to update.

Author: lukel97