A wrapper block was introduced as a part of fixing KT-59748, but was
assigned a real source, which had `getOrBuildFir` confused because
of the incorrectly built `KtToFirMapping`
It is relevant for:
- `if`, `when` expressions with an assignment as a single expression
- Kotlin code fragments,
when the assignment is being analysed as a single expression
in the fragment
^KT-66411 Fixed
Roman Golyshev