Remove vim edit modes from the 4 files that have them

Summary: These are the only files out of hundreds in folly that have them, so just remove them entirely.

Reviewed By: yfeldblum

Differential Revision: D25612198

fbshipit-source-id: 88d4f5c2ffa08d45d0a901c9ef874cddc2730291

folly/experimental/ReadMostlySharedPtr.h

@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 
-/* -*- Mode: C++; tab-width: 2; c-basic-offset: 2; indent-tabs-mode: nil -*- */
 #pragma once
 
 #include <atomic>

folly/experimental/test/ReadMostlySharedPtrBenchmark.cpp

@@ -14,8 +14,6 @@
  * limitations under the License.
  */
 
-/* -*- Mode: C++; tab-width: 2; c-basic-offset: 2; indent-tabs-mode: nil -*- */
-
 #include <folly/experimental/ReadMostlySharedPtr.h>
 
 #include <iostream>

folly/experimental/test/ReadMostlySharedPtrTest.cpp

@@ -14,8 +14,6 @@
  * limitations under the License.
  */
 
-/* -*- Mode: C++; tab-width: 2; c-basic-offset: 2; indent-tabs-mode: nil -*- */
-
 #include <atomic>
 #include <condition_variable>
 #include <mutex>

folly/test/SingletonBenchmark.cpp

@@ -14,8 +14,6 @@
  * limitations under the License.
  */
 
-/* -*- Mode: C++; tab-width: 2; c-basic-offset: 2; indent-tabs-mode: nil -*- */
-
 #include <folly/Singleton.h>
 
 #include <iostream>