K2: make qualifier & classifier the same tower level

#KT-65789 Fixed
#KT-38031 Fixed

compiler/fir/analysis-tests/testData/resolve/problems/javaQualifier.fir.txt

@@ -1,6 +1,6 @@
 FILE: main.kt
     public final fun main(): R|kotlin/Unit| {
-        Q|W|.R|/W.E*s|().R|kotlin/String.length|
+        Q|W|.<Ambiguity: E, [/W.E, /W.E.E]>#().<Unresolved name: length>#
         Q|W.E|.<Unresolved name: length>#
         Q|W.E|.R|/W.E.w*s|
     }

compiler/fir/analysis-tests/testData/resolve/problems/javaQualifier.kt

@@ -1,3 +1,5 @@
+// ISSUE: KT-38031
+
 // FILE: W.java
 public class W {
     public static class E {
@@ -11,7 +13,7 @@ public class W {
 
 // FILE: main.kt
 fun main() {
-    W.E().length // ambiguity in old FE, resolved to static method in FIR
+    W.<!OVERLOAD_RESOLUTION_AMBIGUITY!>E<!>().<!UNRESOLVED_REFERENCE!>length<!> // ambiguity in both FIR / old FE
     W.E.<!UNRESOLVED_REFERENCE!>length<!> // resolved with error to the class W.E in FIR and old FE
     W.E.w // resolved to static field W.e.W in FE
 }

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/tower/FirTowerResolveTask.kt

@@ -269,7 +269,7 @@ internal open class FirTowerResolveTask(
                     else -> null
                 }
             ),
-            info, TowerGroup.Qualifier
+            info, TowerGroup.QualifierOrClassifier
         )
     }
 
@@ -284,7 +284,7 @@ internal open class FirTowerResolveTask(
         val scope = qualifierReceiver.classifierScope() ?: return
         processLevel(
             scope.toScopeTowerLevel(constructorFilter = ConstructorFilter.OnlyNested), info,
-            TowerGroup.Classifier
+            TowerGroup.QualifierOrClassifier
         )
     }
 

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/tower/TowerGroup.kt

@@ -29,9 +29,7 @@ sealed class TowerGroupKind(val index: Byte) : Comparable<TowerGroupKind> {
 
     data object Start : TowerGroupKind(0b0)
 
-    data object Qualifier : TowerGroupKind(1)
-
-    data object Classifier : TowerGroupKind(2)
+    data object QualifierOrClassifier : TowerGroupKind(1)
 
     class TopPrioritized(depth: Int) : WithDepth(3, depth)
 
@@ -176,9 +174,7 @@ private constructor(
 
         val Start = kindOf(TowerGroupKind.Start)
 
-        val Qualifier = kindOf(TowerGroupKind.Qualifier)
-
-        val Classifier = kindOf(TowerGroupKind.Classifier)
+        val QualifierOrClassifier = kindOf(TowerGroupKind.QualifierOrClassifier)
 
         val QualifierValue = kindOf(TowerGroupKind.QualifierValue)