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.
The current backend uses direct field access to the backing field
instead of calling the companion object accessor, which calls
an accessibility bridge, which then gets the field for code such as:
```
class A {
companion object {
val s: String = "OK"
}
// f uses direct access to the A.s backing field.
fun f() = s
}
```
This change does the same for the IR backend.
Dmitriy Novozhilov