FirRenderer: extract separate printer & visitor

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

@@ -50,12 +50,14 @@ fun CFGNode<*>.render(): String =
 
                 is ConstExpressionNode -> "Const: ${fir.render()}"
                 is VariableDeclarationNode ->
-                    "Variable declaration: ${buildString {
-                        FirRenderer(
-                            this,
-                            CfgRenderMode
-                        ).visitCallableDeclaration(fir)
-                    }}"
+                    "Variable declaration: ${
+                        buildString {
+                            FirRenderer(
+                                this,
+                                CfgRenderMode
+                            ).Visitor().visitCallableDeclaration(fir)
+                        }
+                    }"
 
                 is VariableAssignmentNode -> "Assignment: ${fir.lValue.render(CfgRenderMode)}"
                 is FunctionCallNode -> "Function call: ${fir.render(CfgRenderMode)}"