KT-44278 KT-26060 KT-42621
In the compiler, this function was used in psi2ir (and it affected nullability annotations in the resulting JVM class files), in "useless elvis with null on the right side" diagnostic checker, and in light classes. #KT-42650 Fixed
Fixes KT-40115 & KT-40117. Move FlexibleNullability annotation to 'kotlin.internal.ir'.