MediaFramework movies not playing properly in Shipping

`check(Samples.Pop());`
this kind of `Pop()` inside of a `check()` is in a few places in MediaSampleQueue.h and MediaSamples.cpp
but `check()` expands to nothing in Shipping/Test, so, required work was not being done
So MediaFramework stuff does not work in Shipping builds.

Some of this was fixed in CL-3706798, but other instances remain.

Still see about 5 instances of check(Pop()) in MediaSamples.cpp in Release-4.18

There are also some platform specific cases.

All of the cases I have found so far I shelved a fix for in 3740394, but different platforms have different implementations, so they should all be tested.

1. Create a shipping build of ContentExamples and go to the "Media" map
2. Notice that the movies don't play correctly