[llvm] [llvm][unittests] add NDEBUG for some unittests (PR #80821)

[via llvm-commits]

huaatian wrote:

And also, when the user enables EXPENSIVE_CHECKS and NDEBUG, there is no prompt that such settings are wrong, but these two unit tests will fail. I think this is an issue.

https://github.com/llvm/llvm-project/pull/80821