Reimplement the same hacky approach used in the old backend (see
cc2fe6b0c6).
Previously, the debugger incorrectly stepped into Collections.kt on
"step over" inline function calls from stdlib like 'any'.
Since `if` and `when` expressions are represented the same way in IR,
the behavior is fixed for both of them. It's not the case in the old JVM
backend, where stepping over `when` conditions still suffers from the
same problem, which the newly added test checks.
Alexander Udalov