fix [2599939] "cannot play video" after open/close a video player a dozen of times

get rid off the MAP_ONCE flag is MemoryHeapBase (as well as it's functionality),
this feature should not be used anymore.

the software renderer was incorrectly using the default ctor which set MAP_ONCE,
causing the leak. the software renderer itself is incorrectly used while coming
back from sleep.

Change-Id: I123621f8d140550b864f352bbcd8a5729db12b57