Disable MSAN for MicroLock functions

Summary: Even though `folly::MicroLock` is 1 byte, `detail::Futex<>` (aka `std::atomic<uint32_t>`) operates on 4 bytes. So 3 bytes are accessed but not used in any way. So we need to disable memory sanitizer.

Reviewed By: andriigrynenko

Differential Revision: D26082888

fbshipit-source-id: fe585b60c96f48c02df69d182bd75a8eccde2a42

folly/MicroLock.h

@@ -159,14 +159,14 @@ class MicroLockCore {
   }
 
   template <typename Func>
-  FOLLY_DISABLE_ADDRESS_SANITIZER void unlockAndStoreWithModifier(
-      Func modifier) noexcept;
+  FOLLY_DISABLE_ADDRESS_SANITIZER FOLLY_DISABLE_MEMORY_SANITIZER void
+  unlockAndStoreWithModifier(Func modifier) noexcept;
 
  public:
   /**
    * Loads the data stored in the unused bits of the lock atomically.
    */
-  FOLLY_DISABLE_ADDRESS_SANITIZER uint8_t
+  FOLLY_DISABLE_ADDRESS_SANITIZER FOLLY_DISABLE_MEMORY_SANITIZER uint8_t
   load(std::memory_order order = std::memory_order_seq_cst) const noexcept {
     return decodeDataFromWord(word()->load(order));
   }
@@ -176,7 +176,7 @@ class MicroLockCore {
    * used by the lock, the most significant 2 bits of the provided value will be
    * ignored.
    */
-  FOLLY_DISABLE_ADDRESS_SANITIZER void store(
+  FOLLY_DISABLE_ADDRESS_SANITIZER FOLLY_DISABLE_MEMORY_SANITIZER void store(
       uint8_t value,
       std::memory_order order = std::memory_order_seq_cst) noexcept;
 
@@ -270,9 +270,11 @@ class MicroLockBase : public MicroLockCore {
    * data, in which case reading and locking should be done in one atomic
    * operation.
    */
-  FOLLY_DISABLE_ADDRESS_SANITIZER uint8_t lockAndLoad() noexcept;
+  FOLLY_DISABLE_ADDRESS_SANITIZER FOLLY_DISABLE_MEMORY_SANITIZER uint8_t
+  lockAndLoad() noexcept;
   void lock() noexcept { lockAndLoad(); }
-  FOLLY_DISABLE_ADDRESS_SANITIZER bool try_lock() noexcept;
+  FOLLY_DISABLE_ADDRESS_SANITIZER FOLLY_DISABLE_MEMORY_SANITIZER bool
+  try_lock() noexcept;
 
   /**
    * A lock guard which allows reading and writing to the unused bits of the