Reformat imports to a consistent style for imports

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

ledger/tests/blockstore.rs

@@ -1,11 +1,12 @@
-use solana_entry::entry;
-use solana_ledger::{
-    blockstore::{self, Blockstore},
-    get_tmp_ledger_path_auto_delete,
+use {
+    solana_entry::entry,
+    solana_ledger::{
+        blockstore::{self, Blockstore},
+        get_tmp_ledger_path_auto_delete,
+    },
+    solana_sdk::hash::Hash,
+    std::{sync::Arc, thread::Builder},
 };
-use solana_sdk::hash::Hash;
-use std::sync::Arc;
-use std::thread::Builder;
 
 #[test]
 fn test_multiple_threads_insert_shred() {

ledger/tests/shred.rs

@@ -1,19 +1,21 @@
 #![allow(clippy::integer_arithmetic)]
-use solana_entry::entry::Entry;
-use solana_ledger::shred::{
-    max_entries_per_n_shred, verify_test_data_shred, Shred, Shredder,
-    MAX_DATA_SHREDS_PER_FEC_BLOCK, SIZE_OF_DATA_SHRED_PAYLOAD,
-};
-use solana_sdk::{
-    clock::Slot,
-    hash::Hash,
-    signature::{Keypair, Signer},
-    system_transaction,
-};
-use std::{
-    collections::{BTreeMap, HashSet},
-    convert::TryInto,
-    sync::Arc,
+use {
+    solana_entry::entry::Entry,
+    solana_ledger::shred::{
+        max_entries_per_n_shred, verify_test_data_shred, Shred, Shredder,
+        MAX_DATA_SHREDS_PER_FEC_BLOCK, SIZE_OF_DATA_SHRED_PAYLOAD,
+    },
+    solana_sdk::{
+        clock::Slot,
+        hash::Hash,
+        signature::{Keypair, Signer},
+        system_transaction,
+    },
+    std::{
+        collections::{BTreeMap, HashSet},
+        convert::TryInto,
+        sync::Arc,
+    },
 };
 
 type IndexShredsMap = BTreeMap<u32, Vec<Shred>>;