gi test: relax assertion in test_n_methods
gi test: relax assertion in test_n_methods

In gobject-introspection-1.40.0, @info.n_methods returns 62.
But, in gobject-introspection-1.42.0, @info.n_methods returns 63.

`@info.n_methods` is expected to return vaule >=62.

kitachro/ruby-gnome2,kitachro/ruby-gnome2,kitachro/ruby-gnome2,kitachro/ruby-gnome2,kitachro/ruby-gnome2