I've never seen a statement by Hitler or any other Nazi that the Jews and Aryans had a common ancestor. Until someone shows me something like that, it's hard to take claims of nazis knowing evolution seriously.
Common descent does not a Darwinist make: even some ID people accept it.
The true indication that Hitler didn't accept Darwinism, however he might have exploited Darwin's name, is that his entire ideology was based on the concept of "racial purity", which flies (pbbblt), flies (pbbblt) right in Darwinism's face.
A true Darwinist would have promoted racial mixing, as genetic diversity is the real key to survival, and survival is all that Darwinism is about. To a Darwinist, miscegenation is a virtue, not a sin.
Moreover, a cursory glance at the history of human accomplishment shows that the Jews have a better claim than anybody on being the "master race", if you believe the misconception that the "purpose of evolution" is to make the human race smarter and more creative, and the misconception that all ability is genetic.