Due to inlining, we can now see unexported functions and variables,
and functions and variables imported from different packages.
Ignore them rather than reporting them from this package.
Handle $hash and $equal functions consistently, so that we discard the
inline body if there is one.
Ignore names created for result parameters for inlining purposes.
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/180758
From-SVN: r272023
ffaa3a1c74