Remove "mediafilter" renderscript test binary.

This hasn't been meaningfully touched since 2014, appears to have only
ever been a kind of test binary, and isn't shipped on the device.

As part of the work to move beyond renderscript deprecation (a couple of
years ago) to renderscript removal, remove this rather than port it to
C++.

Bug: http://b/256932140
Test: treehugger
Change-Id: Ia56d55e110ebd185f6bfb0014fef77dfcc8d58fa
Merged-In: Ia56d55e110ebd185f6bfb0014fef77dfcc8d58fa