FIR CFA: remove modes

They are only used in one place that can just as well use kinds.

Especially considering that "the one place" used them incorrectly and
would not attach local functions in property accessors as subgraphs.

compiler/fir/semantics/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraph.kt

@@ -73,13 +73,13 @@ class ControlFlowGraph(val declaration: FirDeclaration?, val name: String, val k
     enum class Kind(val withBody: Boolean) {
         Function(withBody = true),
         AnonymousFunction(withBody = true),
-        ClassInitializer(withBody = true),
+        ClassInitializer(withBody = false),
         PropertyInitializer(withBody = true),
         FieldInitializer(withBody = true),
         TopLevel(withBody = false),
         AnnotationCall(withBody = true),
-        DefaultArgument(withBody = false),
-        Stub(withBody = true)
+        DefaultArgument(withBody = true),
+        Stub(withBody = false)
     }
 }