Otherwise `debug/stepping/enum.kt` starts failing as soon as we advance
default language version to 1.9, because with the introduction of enum
entries, enum's `<clinit>` now invokes LambdaMetafactory which invokes
its own bundled version of ASM located in
`jdk.internal.org.objectweb.asm`, so we end up stepping over a lot of
internal ASM code.
`jdk.internal.*` is also excluded by default in the debugger settings in
IntelliJ, so users will not observe this issue in practice.
Alexander Udalov
3dc3ed4ca5