Support single-element annotations

If an annotation accepts a single parameter named "value", it is
possible to omit the parameter name. This is similar to the
single-element annotation in Java (JLS, section 9.7.3 Single-Element
Annotations[1]).

[1] https://docs.oracle.com/javase/specs/jls/se17/html/jls-9.html#jls-9.7

Test: atest --host aidl_unittests
Change-Id: I38ab77ea13de9dd55adcbb9d63104b71b0dbe92b
2 files changed