[FIR] Get rid of candidateSymbol in FirNamedReference

`candidateSymbol` has any reasonable meaning only for references with
  not completed candidate, so this property is moved from FirNamedReference
  to new node FirNamedReferenceWithCandidateSymbol, which has real
  implementation only in :resolve module (`FirNamedReferenceWithCandidate`)

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/FirTreeBuilder.kt

@@ -152,6 +152,7 @@ object FirTreeBuilder : AbstractFirTreeBuilder() {
     val wrappedDelegateExpression by element(Expression, wrappedExpression)
 
     val namedReference by element(Reference, reference)
+    val namedReferenceWithCandidateBase by element(Reference, namedReference)
     val errorNamedReference by element(Reference, namedReference, diagnosticHolder)
     val superReference by element(Reference, reference)
     val thisReference by element(Reference, reference)

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/ImplementationConfigurator.kt

@@ -111,7 +111,7 @@ object ImplementationConfigurator : AbstractFirTreeImplementationConfigurator()
         impl(callableReferenceAccess)
 
         impl(componentCall) {
-            default("calleeReference", "FirSimpleNamedReference(source, Name.identifier(\"component\$componentIndex\"), null)")
+            default("calleeReference", "FirSimpleNamedReference(source, Name.identifier(\"component\$componentIndex\"))")
             useTypes(simpleNamedReferenceType, nameType)
             optInToInternals()
         }
@@ -404,27 +404,22 @@ object ImplementationConfigurator : AbstractFirTreeImplementationConfigurator()
             }
         }
 
-        impl(resolvedNamedReference) {
-            defaultNull("candidateSymbol", withGetter = true)
-        }
+        impl(resolvedNamedReference)
 
         impl(resolvedNamedReference, "FirPropertyFromParameterResolvedNamedReference") {
-            defaultNull("candidateSymbol", withGetter = true)
             publicImplementation()
         }
 
-        impl(resolvedErrorReference) {
-            defaultNull("candidateSymbol", withGetter = true)
-        }
+        impl(resolvedErrorReference)
 
-        impl(resolvedCallableReference) {
-            defaultNull("candidateSymbol", withGetter = true)
-        }
+        impl(resolvedCallableReference)
 
         impl(namedReference, "FirSimpleNamedReference") {
-            kind = OpenClass
+            publicImplementation()
         }
 
+        noImpl(namedReferenceWithCandidateBase)
+
         impl(delegateFieldReference) {
             default("name") {
                 value = "Name.identifier(\"\\\$delegate\")"

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/NodeConfigurator.kt

@@ -620,7 +620,10 @@ object NodeConfigurator : AbstractFieldConfigurator<FirTreeBuilder>(FirTreeBuild
 
         namedReference.configure {
             +name
-            +field("candidateSymbol", firBasedSymbolType, "*", nullable = true)
+        }
+
+        namedReferenceWithCandidateBase.configure {
+            +field("candidateSymbol", firBasedSymbolType, "*")
         }
 
         resolvedNamedReference.configure {