don't try to visit probe file

this file is only created for a brief moment during the bins checks
in the source directories while other checks may also be visiting
that directory. skip processing it to avoid missing file errors

Author: the8472

src/tools/tidy/src/lib.rs

@@ -53,6 +53,7 @@ pub mod unstable_book;
 
 fn filter_dirs(path: &Path) -> bool {
     let skip = [
+        "tidy-test-file",
         "compiler/rustc_codegen_cranelift",
         "src/llvm-project",
         "library/backtrace",