The light is constant, which means it moves at the same speed in both cases (assuming the light is in a vacuum). It won't move faster or slower based on the gravity field (other than in the case of black hole where it can't escape at all).

What happens instead is that the speed that an object moves through space-time changes dependent upon gravity. Using an atomic clock, we've actually measured the effect of gravity to show that time moves more slowly down on earth than it does in an orbiting satellite.