FIR CFG traverser: do not skip graph enter node

#KT-42348 fixed

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/cfa/CfgTraverser.kt

@@ -58,19 +58,17 @@ private fun <I : ControlFlowInfo<I, K, V>, K : Any, V : Any> ControlFlowGraph.co
         if (direction == TraverseDirection.Backward && node is CFGNodeWithCfgOwner<*>) {
             node.subGraphs.forEach { it.collectDataForNodeInternal(direction, initialInfo, visitor, nodeMap, changed) }
         }
-        if (!(node.isEnterNode(direction) && node.owner.owner == null)) {
-            val previousNodes = when (direction) {
-                TraverseDirection.Forward -> node.previousCfgNodes
-                TraverseDirection.Backward -> node.followingCfgNodes
-            }
-            val previousData = previousNodes.mapNotNull { nodeMap[it] }
-            val data = nodeMap[node]
-            val newData = node.accept(visitor, previousData)
-            val hasChanged = newData != data
-            changed[node] = hasChanged
-            if (hasChanged) {
-                nodeMap[node] = newData
-            }
+        val previousNodes = when (direction) {
+            TraverseDirection.Forward -> node.previousCfgNodes
+            TraverseDirection.Backward -> node.followingCfgNodes
+        }
+        val previousData = previousNodes.mapNotNull { nodeMap[it] }
+        val data = nodeMap[node]
+        val newData = node.accept(visitor, previousData)
+        val hasChanged = newData != data
+        changed[node] = hasChanged
+        if (hasChanged) {
+            nodeMap[node] = newData
         }
         if (direction == TraverseDirection.Forward && node is CFGNodeWithCfgOwner<*>) {
             node.subGraphs.forEach { it.collectDataForNodeInternal(direction, initialInfo, visitor, nodeMap, changed) }

compiler/testData/diagnostics/tests/controlFlowAnalysis/assignedInIfElse.fir.kt

@@ -1,16 +0,0 @@
-fun foo(arg: Boolean) {
-    val x : Int
-    if (arg) {
-        x = 4
-    } else {
-        x = 2
-    }
-
-    x.hashCode()
-
-    class Local {
-        fun bar() {
-            <!UNINITIALIZED_VARIABLE!>x<!>.hashCode()
-        }
-    }
-}

compiler/testData/diagnostics/tests/controlFlowAnalysis/assignedInIfElse.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 fun foo(arg: Boolean) {
     val x : Int
     if (arg) {