Add missing includes on linux

RootSet.cpp

@@ -169,8 +169,10 @@ RootSet::~RootSet() {
 }
 
 #ifdef ENABLE_ROOTSET_TESTS
+#include <atomic>
 #include <latch>
 #include <thread>
+#include <vector>
 
 int main() {
   constexpr int kNumReaders = 3;
@@ -211,4 +213,4 @@ int main() {
     t.join();
   }
 }
-#endif
+#endif