This fixes some cases where we infer some type variable inside one
of the branches to Nothing instead of the expected type because Nothing
appeared in some other branch.
Specifically, we add an equality instead of a subtype constraint during
completion of calls to synthetic functions for if/when, try and !!.
We don't do it when the call contains a (possibly nested) elvis or is
inside the RHS of an assignment.
Otherwise, we would prevent some smart-casts.
#KT-65882 Fixed
Some of the changed tests may duplicate other existing diagnostics,
but that should not be reason not to report them at all.
There might be another job to be done to avoid diagnostic duplications
This directive anyway does not make test run twice with OI, and with NI
It only once run the test with specific settings (// LANGUAGE)
and ignores irrelevant (OI or NI tags)
Kirill Rakhman