fix violation of warning maybe-uninitialized in hazptr_array

Reviewed By: ilvokhin

Differential Revision: D68424716

fbshipit-source-id: 6a4fadb4e9895f5781a233d9b67a74f0c2233987

third-party/folly/src/folly/synchronization/HazptrHolder.h

@@ -231,7 +231,7 @@ class hazptr_array {
   static_assert(M > 0, "M must be a positive integer.");
 
   aligned_hazptr_holder<Atom> raw_[M];
-  bool empty_;
+  bool empty_{true};
 
   friend hazptr_array<M, Atom> make_hazard_pointer_array<M, Atom>();
 
@@ -240,7 +240,7 @@ class hazptr_array {
 
  public:
   /** Default empty constructor */
-  FOLLY_ALWAYS_INLINE hazptr_array() noexcept : empty_(true) {
+  FOLLY_ALWAYS_INLINE hazptr_array() noexcept {
     auto h = reinterpret_cast<hazptr_holder<Atom>*>(&raw_);
     for (uint8_t i = 0; i < M; ++i) {
       new (&h[i]) hazptr_holder<Atom>();