These tests were initially testing that $EntriesMappings classes were
correctly generated, but started to check something else once the
language feature EnumEntries was enabled by default.
Leveraging the same mechanism with $EntriesMapping as Java enums.
Old (compiled with LV/AV < 1.8) enums are detected by looking for
static special <get-entries> method that cannot be introduced on
Kotlin enums otherwise
#KT-53236