vndk-def: Rename VNDK-stable to VNDK-SP

This commit renames VNDK-stable to VNDK-SP because libraries in VNDK-SP
don't have to be stable.

Bug: 37867089
Test: ./tests/run.py
Change-Id: I75d966e05c274e369b5d54e2d661cc63997e1c00
Merged-In: I73697af3403b21db4878cadcf1622a9ac92ed10b
2 files changed