[clang] [clang-tools-extra] [compiler-rt] [lldb] [llvm] [mlir] [openmp] [polly] fix(python): fix comparison to None (PR #91857)

[Maksim Levental via llvm-commits]

makslevental wrote:

It's a `sed s/== None/is None/g` - what is there to review? 10 separate PRs for the same exact `sed` costs more in commit noise (and effort on the part of @e-kwsm) than one solid, patient, review here.

https://github.com/llvm/llvm-project/pull/91857