Update shared_ptr casts.

[SVN r81463]

test/Jamfile.v2

@@ -74,6 +74,7 @@ import testing ;
           [ compile sp_array_cv_test.cpp ]
           [ run sp_convertible_test.cpp ]
           [ run sp_array_n_test.cpp ]
+          [ run sp_array_cast_test.cpp ]
 
           [ compile-fail array_fail_spa_sp_c.cpp ]
           [ compile-fail array_fail_sp_spa_c.cpp ]