calculate_accounts_hash does not throttle threads on startup (#17338)

runtime/src/accounts_db.rs

@@ -3973,8 +3973,7 @@ impl AccountsDb {
         // We'll also accumulate the lamports within each chunk and fewer chunks results in less contention to accumulate the sum.
         let chunks = crate::accounts_hash::MERKLE_FANOUT.pow(4);
         let total_lamports = Mutex::<u64>::new(0);
-        let hashes: Vec<Vec<Hash>> = {
-            self.thread_pool_clean.install(|| {
+        let get_hashes = || {
             keys.par_chunks(chunks)
                 .map(|pubkeys| {
                     let mut sum = 0u128;
@@ -4033,9 +4032,13 @@ impl AccountsDb {
                     *total =
                         AccountsHash::checked_cast_for_capitalization(*total as u128 + sum);
                     result
-                    })
-                    .collect()
-            })
+                }).collect()
+        };
+
+        let hashes: Vec<Vec<Hash>> = if check_hash {
+            get_hashes()
+        } else {
+            self.thread_pool_clean.install(get_hashes)
         };
         if mismatch_found.load(Ordering::Relaxed) > 0 {
             warn!(