Reformat imports to a consistent style for imports

rustfmt.toml configuration:
  imports_granularity = "One"
  group_imports = "One"

runtime/src/read_only_accounts_cache.rs

@@ -1,20 +1,21 @@
 //! ReadOnlyAccountsCache used to store accounts, such as executable accounts,
 //! which can be large, loaded many times, and rarely change.
-use dashmap::{mapref::entry::Entry, DashMap};
 //use mapref::entry::{Entry, OccupiedEntry, VacantEntry};
-use solana_sdk::{
-    account::{AccountSharedData, ReadableAccount},
-    clock::Slot,
-    pubkey::Pubkey,
-};
-use std::thread::{sleep, Builder, JoinHandle};
-use std::time::Duration;
-use std::{
-    sync::{
-        atomic::{AtomicBool, AtomicU64, AtomicUsize, Ordering},
-        Arc, RwLock,
+use {
+    dashmap::{mapref::entry::Entry, DashMap},
+    solana_sdk::{
+        account::{AccountSharedData, ReadableAccount},
+        clock::Slot,
+        pubkey::Pubkey,
+    },
+    std::{
+        sync::{
+            atomic::{AtomicBool, AtomicU64, AtomicUsize, Ordering},
+            Arc, RwLock,
+        },
+        thread::{sleep, Builder, JoinHandle},
+        time::{Duration, Instant},
     },
-    time::Instant,
 };
 
 type ReadOnlyCacheKey = (Pubkey, Slot);
@@ -240,8 +241,10 @@ impl ReadOnlyAccountsCache {
 
 #[cfg(test)]
 pub mod tests {
-    use super::*;
-    use solana_sdk::account::{accounts_equal, Account, WritableAccount};
+    use {
+        super::*,
+        solana_sdk::account::{accounts_equal, Account, WritableAccount},
+    };
     #[test]
     fn test_accountsdb_sizeof() {
         // size_of(arc(x)) does not return the size of x