Add tests for std::move wrapper

tests/run/cpp_move.pyx

+# mode: run
+# tag: cpp, werror, cpp11
+
+from libcpp cimport nullptr
+from libcpp.memory cimport shared_ptr, make_shared
+from libcpp.utility cimport move
+from cython.operator cimport dereference
+
+cdef extern from *:
+    """
+    #include <string>
+
+    template<typename T> const char* move_helper(T&) { return "lvalue-ref"; }
+    template<typename T> const char* move_helper(T&&) { return "rvalue-ref"; }
+    """
+    const char* move_helper[T](T)
+
+def test_move_assignment():
+    """
+    >>> test_move_assignment()
+    """
+    cdef shared_ptr[int] p1, p2
+    p1 = make_shared[int](1337)
+    p2 = move(p1)
+    assert p1 == nullptr
+    assert dereference(p2) == 1337
+
+def test_move_func_call():
+    """
+    >>> test_move_func_call()
+    """
+    cdef shared_ptr[int] p
+    assert move_helper(p) == b'lvalue-ref'
+    assert move_helper(move(p)) == b'rvalue-ref'