As someone who worked in Nokia developer relations, I have no idea what you're talking about. Aside from the Nokia X (which is Android), no Nokia product has ever done anything to "make their mobile platform popular by supporting existing Android apps"
-Symbian didn't
-MeeGo didn't (sigh, my beautiful N9...)
-Windows Phone didn't
-S40 didn't
You might be confusing Nokia with BlackBerry, which did make Android support a feature of BB10.
Yeah, that never happened. It may be a reference to Alien Dalvik being rumored to be included w/the first actual MeeGo release (Not N9, which was branded MeeGo, but was really still Maemo.) Critics of this speculated that this would keep developers from developing native apps, and now, in the haze of ancient history and a lack of fact checking, a few people think that this actually happened and are using it as a parable to inform future strategies.
History is very slippery.
edit: Looks like there were press releases about it being available for N9 and N900. My history is slippery, too:) It never was.
-Symbian didn't
-MeeGo didn't (sigh, my beautiful N9...)
-Windows Phone didn't
-S40 didn't
You might be confusing Nokia with BlackBerry, which did make Android support a feature of BB10.