[LoopVectorize] Enhance Vectorization decisions for predicate tail-folded...

[LoopVectorize] Enhance Vectorization decisions for predicate tail-folded loops with low trip counts (#69588)

* Avoid using `CM_ScalarEpilogueNotAllowedLowTripLoop` for loops known
to be predicate tail-folded, delegating to `areRuntimeChecksProfitable`
to decide on the profitability of vectorizing loops with runtime checks.
* Update the `areRuntimeChecksProfitable` function to consider the
`ScalarEpilogueLowering` setting when assessing vectorization of a loop.

With this patch, we can make more informed decisions for loops with low
trip counts, especially when leveraging Profile-Guided Optimization
(PGO) data.