Fix ThreadCachedInts init

Summary: The domain tests seem broken.  Digging in, it seems to be uninitialized ThreadCachedInts variables.  Initialize them.

Reviewed By: yfeldblum

Differential Revision: D7505520

fbshipit-source-id: aca8a6f5b38271bf06ea8a6377bfb692328f1e33

folly/synchronization/detail/ThreadCachedInts.h

@@ -36,8 +36,8 @@ namespace detail {
 
 template <typename Tag>
 class ThreadCachedInts {
-  std::atomic<int64_t> orphan_inc_[2];
-  std::atomic<int64_t> orphan_dec_[2];
+  std::atomic<int64_t> orphan_inc_[2] = {};
+  std::atomic<int64_t> orphan_dec_[2] = {};
   folly::detail::Futex<> waiting_{0};
 
   class Integer {

folly/synchronization/test/RcuTest.cpp

@@ -171,7 +171,7 @@ TEST(RcuTest, Synchronize) {
 TEST(RcuTest, NewDomainTest) {
   struct UniqueTag;
   rcu_domain<UniqueTag> newdomain(nullptr);
-  synchronize_rcu();
+  synchronize_rcu(&newdomain);
 }
 
 TEST(RcuTest, NewDomainGuardTest) {