tests: accept llvm intrinsic in align-checking test
This changed in upstream change https://reviews.llvm.org/D98152 (aka
https://github.com/llvm/llvm-project/commit/
a266af721153fab6452094207b09ed265ab0be7b)
wherein LLVM got smarter about using intrinsics. As best I can tell the
change I've made here preserves the intent of the test on LLVM 14 and
before while also passing on LLVM 15 and later.