Change C++ output file name rule regarding non-versioned module

As-is: foo->foo-V1-cpp.so, foo-unstable->foo-unstable-cpp.so
To-be: foo->foo-cpp.so, foo-unstable->foo-V1-cpp.so

To mitigate the changes in vndk list during adding a new aidl_interface
included in VNDK, change output file name rule for an <name>-unstable

There might be a similar problem when existing interface imports an new
aidl_interface, but the structured version field[^1] can cope with the problem.

[^1] such as version: "1", imports: ["B-V2"], } which is b/146436251's goal

Bug: 146436251
Test: m
Change-Id: I700ca553a544ec424526734c014d0559b1f9f139
2 files changed