Add test using global placeholders

test/Jamfile.v2

@@ -72,3 +72,4 @@ run mem_fn_fastcall_test.cpp ;
 run mem_fn_stdcall_test.cpp ;
 run bind_noexcept_test.cpp ;
 run bind_noexcept_mf_test.cpp ;
+run global_placeholders.cpp ;