Update Kokkos library in LAMMPS to v3.4.0

lib/kokkos/cmake/compile_tests/cplusplus14.cpp

@@ -0,0 +1,8 @@
+#include <type_traits>
+
+int main() {
+  // _t versions of type traits were added in C++14
+  std::remove_cv_t<int> i = 0;
+
+  return i;
+}