The number of tests does not depend on the architecture's pointer width

Use `u32` instead of `usize` for counting them.

src/tools/tidy/src/ui_tests.rs

@@ -12,10 +12,10 @@ use std::path::{Path, PathBuf};
 // should all be 1000 or lower. Limits significantly smaller than 1000 are also
 // desirable, because large numbers of files are unwieldy in general. See issue
 // #73494.
-const ENTRY_LIMIT: usize = 900;
+const ENTRY_LIMIT: u32 = 900;
 // FIXME: The following limits should be reduced eventually.
 
-const ISSUES_ENTRY_LIMIT: usize = 1676;
+const ISSUES_ENTRY_LIMIT: u32 = 1676;
 
 const EXPECTED_TEST_FILE_EXTENSIONS: &[&str] = &[
     "rs",     // test source files
@@ -52,7 +52,7 @@ const EXTENSION_EXCEPTION_PATHS: &[&str] = &[
 ];
 
 fn check_entries(tests_path: &Path, bad: &mut bool) {
-    let mut directories: HashMap<PathBuf, usize> = HashMap::new();
+    let mut directories: HashMap<PathBuf, u32> = HashMap::new();
 
     for dir in Walk::new(&tests_path.join("ui")) {
         if let Ok(entry) = dir {
@@ -61,7 +61,7 @@ fn check_entries(tests_path: &Path, bad: &mut bool) {
         }
     }
 
-    let (mut max, mut max_issues) = (0usize, 0usize);
+    let (mut max, mut max_issues) = (0, 0);
     for (dir_path, count) in directories {
         let is_issues_dir = tests_path.join("ui/issues") == dir_path;
         let (limit, maxcnt) = if is_issues_dir {