Unhide inPreferQualityOverSpeed in BitmapFactory.Options.

The new field allows a developer to use a more accurate by
slightly slower IDCT method in JPEG decode. This in turns improves the
quality of the reconstructed image.

The field by default is not set and thus does not affect existing
applications.

Bug: 3238925

Related changes: https://android-git.corp.google.com/g/#change,83291 and
                 https://android-git.corp.google.com/g/#change,83294

Change-Id: I969f5c413f9b2179454aeb90e18ae8222ee583b4