[polly] Bound ISL operations during pre-vectorization (PR #165204)

[Shikhar Jain via llvm-commits]

ShikharjQUIC wrote:

Bound ISL operations during pre-vectorization to
prevent indefinite compilation. The MaxOpGuard
previously used for schedule computation is now
extended to also guard pre-vectorization optimizations.
This patch includes a reduced test case derived
from the original bug report.

Author: Michael Kruse
             ShikharjQUIC

https://github.com/llvm/llvm-project/pull/165204