menu: dropdown doesn't inherit dark theme

[rudzikdawid]

example of issue: https://codepen.io/anon/pen/qoxORQ?editors=1010

using dark theme and md-menu causes render issue: light background.
material2 has proper implementation: dark menu in dark theme, light menu in light theme.
But in material1 we have light background in dark theme;

md-menu has the same problem as md-select #3379 #11198