The bending depends on the field, not on the mass; so, regardless of the mass, all other factors being equal, the bending is the same

So in this respect, Newtonian mechanics and GR are in agreement.

It turns out that General Relativity predicts a bending which is double the one predicted by newtonian mechanichs, and this is exactly what they discovered in 1922.

That's really interesting because Einstein revised GR shortly before the 1922 eclipse when he realized an earlier version's prediction was off by 1/2. So it turns out that earlier prediction would have matched Newtonian mechanics' and, had he not made the change, the eclipse results would have resolved nothing. (They would have embarassed Einstein, though.)

Apparently, this Newtonian prediction wasn't recognized at the time, i.e., the thinking then was that any bending at all would be a violation. So it's a more recent refinement (?)

History of Gravitational Lensing:

http://relativity.livingreviews.org/open?pubNo=lrr-1998-12&page=node2.html<<In the year 1911 - more than a century later - Albert Einstein [50]directly addressed the influence of gravity on light (``Über den Einfluß der Schwerkraft auf die Ausbreitung des Lichtes'' (``On the Influence of Gravity on the Propagation of Light'')). At this time, the General Theory of Relativity was not fully developed. This is the reason why Einstein obtained - unaware of the earlier result - the same value for the deflection angle as Soldner had calculated with Newtonian physics. In this paper, Einstein found

α = 2GM/c

^{2}R = 0.83 arcsec

for the deflection angle of a ray grazing the sun (here M and R are the mass and the radius of the sun, c and G are the velocity of light and the gravitational constant, respectively)

...

With the completion of the General Theory of Relativity, Einstein was the first to derive the correct deflection angle α of a light ray passing at a distance r from an object of mass M as

α = 4GM/c

^{2} *1/r

where G is the constant of gravity and c is the velocity of light. The additional factor of two (compared to the ``Newtonian'' value) reflects the spatial curvature (which is missed if photons are just treated as particles). With the solar values for radius and mass Einstein obtained [51, 52]:

α = 1.74 arcsec

It is common wisdom now that the determination of this value to within 20% during the solar eclipse in 1919 by Arthur Eddington and his group was the second observational confirmation of General Relativity [47] and the basis of Einstein's huge popularity starting in the 1920s. (The first one had been the explanation of Mercury's perihelion shift.) Recently, the value predicted by Einstein was confirmed to an accuracy better than 0.02%>>