Reinstate multi-kernel support in Renderscript.
Reinstate multi-kernel support in Renderscript.


Former-commit-id: 5d580d1200c54ef29bce0285bee13b7b3796d1c0
Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,darkbuck/Halide,darkbuck/Halide,darkbuck/Halide