We are going to deprecate `WITH_RUNTIME` directive. The main reason
behind this change is that `WITH_STDLIB` directive better describes
its meaning, specifically it will add kotlin stdlib to test's classpath.
Otherwise a local class in a field initializer or anonymous init block
is copied into each constructor of the containing class (because
InitializersLowering calls deepCopy).
Since the code structure no longer resembles the original source code
here, record a custom EnclosingMethod mapping before moving such
classes, and use it in codegen.
Ivan Kylchik