This reverts commit 363b2550 (partially)
363b2550
Since many labels are not present in the FIR tree, this checker is implemented as a syntax checker. Comparing with FE1.0, this change reports some REDUNDANT_LABEL_WARNING that FE1.0 has missed, especially LHS of assignments.
This checker doesn't support `@PublishedAPI` yet, so some BB tests for it were muted. #KT-46270
ExtensionFunctionType
#KT-39034 Fixed