Compatibility library support for general reduction.

Requires corresponding change in frameworks/support.

Note that the new RSTest_CompatLib test cases were copied from RsTest.

Also:
- Change LOCAL_RENDERSCRIPT_TARGET_API to 0.
- Change manifest targetSdkVersion from 8 to 24 (see Bug: 27367665).
- Change compile-only RSTest_CompatLib test apitest.rs to use N rather than pre-N
  rsForEach() API.

Bug: 23535724
Change-Id: I872f2b5a83fb78f4b54b8f6710e1d49df3bea3d1
10 files changed