Un-deprecate some deprecated code and fix a couple of hints

pkg/analyzer/lib/src/dart/analysis/file_byte_store.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async';
 import 'dart:io';
 import 'dart:isolate';
 
 import 'package:analyzer/src/dart/analysis/byte_store.dart';
 import 'package:path/path.dart';
 
 /**
  * [ByteStore] that stores values as files.
  */
 class FileByteStore implements ByteStore {
   static bool _cleanUpSendPortShouldBePrepared = true;
   static SendPort _cleanUpSendPort;
 
   final String _cachePath;
-  final String _tempName = 'temp_${pid}';
+  final String _tempName = 'temp_$pid';
   final int _maxSizeBytes;
 
   int _bytesWrittenSinceCleanup = 0;
   bool _evictionIsolateIsRunning = false;
 
   FileByteStore(this._cachePath, this._maxSizeBytes) {
     _requestCacheCleanUp();
   }
 
   @override
@@ skipping 101 matching lines @@
       if (currentSizeBytes < maxSizeBytes) {
         break;
       }
       try {
         await file.delete();
       } catch (_) {}
       currentSizeBytes -= fileStatMap[file].size;
     }
   }
 }