Fix fast-path check when selecting most specific members

Obviously 'overridableGroup' cannot be both empty and having the single element.
'conflictedHandles' that is what meant to be empty instead

core/descriptors/src/org/jetbrains/kotlin/resolve/overridingUtils.kt

@@ -61,7 +61,7 @@ fun <H : Any> Collection<H>.selectMostSpecificInEachOverridableGroup(
         val overridableGroup =
                 OverridingUtil.extractMembersOverridableInBothWays(nextHandle, queue, descriptorByHandle) { conflictedHandles.add(it) }
 
-        if (overridableGroup.size == 1 && overridableGroup.isEmpty()) {
+        if (overridableGroup.size == 1 && conflictedHandles.isEmpty()) {
             result.add(overridableGroup.single())
             continue
         }