Add rsForEachInternal

Bug: 23535985

Added a compiler intrinsic rsParallelFor to the runtime API, which
is translated into an internal API (rsForEachInternal) by slang.

Added a test to RsTest (for native) and RSTest_CompatLib
(for support).

Enhanced the auto api generator to handle ellipsis argument,
intrinsics, internal-only APIs, and special level for API under
development.

Change-Id: I6e2cf3db868f426aa8e0b9a77732b66c1e6b9f03
19 files changed