NB: in order to produce correct IR origins, the source element kinds for
some FIR elements has been changed. As a side effect, mapping PSI to FIR
slightly changed: namely, for `a[b]++`, `a[b]` used to be mapped on
`set` call or callable reference, but now it is mapped on `get` call.
^KT-61891: Fixed
^KT-64387: Fixed
This aligns the behavior with K1 and fixes an issue when the default
value was deserialized as FirExpressionStub leading to an exception
in FIR2IR when trying to convert it to an IR expression.
#KT-60120 Fixed
#KT-59610 Fixed