Wrapper detection can have false positives

[Keno]

The code here tries to detect default argument wrappers by detecting patterns of use of the #self argument. However this is prone to false positive, because there are other kinds of methods that could have such patterns, e.g. Cassette-style context arguments. It would be better to adjust Base to add a new flag to methods that indicate that they're implicitly generated wrappers and set this flag from the frontend.
https://github.com/JuliaDebug/JuliaInterpreter.jl/blob/39d04c70762ab3dd4300be224eb12ab4a79cf608/src/commands.jl#LL233