Remove an API that doesn't exist.

Apparently this was removed in Jelly Bean:
https://stackoverflow.com/q/24312632/632035. Keeping the decl in the
NDK just confuses people: https://stackoverflow.com/q/49646596/632035.

Test: make checkbuild
Bug: None
Change-Id: If549fcd8f4052e633646c4ce8a054a0bbcd8b2bf