Library methods such as 'listOf' are resolved
to have the package fragments as their parents,
but JVM expects their containing file classes as parents.
This fix generates those file classes and
uses them as parent replacements for such library methods.
Before this commit, we had two methods to do generally the same synthetic thing.
It's an attempt to keep only one of them.
Accessor symbols are generated in Java use-site member scopes,
at this place we know better whether we are in Java class or not.
However, we have to do this at every use-site level, which is relatively slow.
Also we could encounter problems when accessor function is overridden in Kotlin,
and accessor symbol can still contain reference to Java accessor.
Most of these tests used this directive as a way to opt in to a new
language feature, and most of those features are already stable for a
long time, so no opt-in is needed. Some other tests used the directive
to opt out from a language feature, replace those by the `LANGUAGE`
directive. One test used the directive to test behavior that actually
depended on the API version; use `API_VERSION` directive there instead.
Denis Zharkov