Fake overrides created by K1, as well as fir2ir in K2, use DEFINED. So
this gets rid of a lot of differences in IR text dumps between the K2
normal mode and K2 with IR fake overrides, and will ultimately help in
implementing and testing KT-61360.
The change in AddContinuationLowering is needed to fix tests like
kt47549. When creating anonymous classes for SAM implementations, we're
reusing the same fake override building machinery. And since we can't
extract any meaningful information from the fake override parameter's
origin anymore, we have to get the parameter from the original symbol.
Level of CFGNode is used to determine which call is a common one for
creating node with union of arguments (to merge flow from multiple
in-place lambdas). Before this change calls in different when branches
may have same node level, which entail passing smartcasts from moddle of
one branch to another
```
val x: Any = ...
when {
... -> run { x as String } // (1)
... -> {
run {
x.foo()
} // (2)
"hello"
}
}
```
Call `(1)` was assumed as argument of call `(2)` which is incorrect
#KT-44814 Fixed
Brian Norman