vndk-def: Implement degenerated VNDK for o-release

This commit implements the degenerated directory layout for o-release.
This commit also simplifies the output significantly.

Bug: 37867089
Test: Run vndk_definition_tool.py against o-release images.
Change-Id: I6fa6833461639ad8dfc6103c0753064c63cdadcb
Merged-In: I5aad29fa4ff7e819778d26d2e2011af1be61bb58
5 files changed