Allow annotations on oneway methods.

Annotations in the parser are applied to *types*, and not declarations. So, while the following would work:

`oneway @UnsupportedAppUsage bar bar();`

It's not right nor readable, as the @UnsupportedAppUsage is meant to be applied to the whole method.

Original changelist: ag/8761743
Exempt-From-Owner-Approval: approved by smoreland@
Bug: 137350495
Test: m && atest aidl_unittests
Change-Id: I967821fb6975cb6889e190732211664f4d708a2b
3 files changed