Remove api-stubs-docs targets.

Since api-stubs-docs will be replaced by Metalava.

Test: m -j checkbuild
Bug: b/70351683 b/78245848
Change-Id: I3d2091afb0b5d93250573076d4dc95b47c634f2d
Merged-In: I3d2091afb0b5d93250573076d4dc95b47c634f2d
1 file changed