[clang-tools-extra] [clang-tidy] Speed up/rewrite `bugprone-stringview-nullptr` (PR #192889)

[Baranov Victor via cfe-commits]

vbvictor wrote:

I wonder if using "RewriteRule" approach make checks slow in general.
New "llvm-use-new-mlir-op-builder" check also seems slow (https://github.com/llvm/llvm-project/pull/175342#issuecomment-4286734451) and it uses Rewrite approach as well. (maybe the check itself is "slow-written" but I don't see anything catchy at first glance)

So we should ether not bother and let people write slow checks (with Rewrite) or ban usage of Rewrite or speed-up it somehow.

This one-time fix may be not the best approach in the long run

https://github.com/llvm/llvm-project/pull/192889