[FIR] Forbid multiple labels per statement

^KT-53629: Fixed

compiler/testData/diagnostics/tests/controlStructures/notAFunctionLabel_before.fir.kt

@@ -30,12 +30,12 @@ fun testAnnotatedLambdaLabel() =
     }
 
 fun testLambdaMultipleLabels1() =
-    lambda1@ lambda2@ {
+    <!MULTIPLE_LABELS_ARE_FORBIDDEN!>lambda1@<!> lambda2@ {
         <!NOT_A_FUNCTION_LABEL!>return@lambda1<!>
     }
 
 fun testLambdaMultipleLabels2() =
-    lambda1@ lambda2@ {
+    <!MULTIPLE_LABELS_ARE_FORBIDDEN!>lambda1@<!> lambda2@ {
         return@lambda2
     }
 
@@ -62,7 +62,7 @@ fun testHighOrderFunctionCallLabelInReturn() {
 }
 
 fun testMultipleLabelsWithNestedLambda() {
-    l1@ l2@{
+    <!MULTIPLE_LABELS_ARE_FORBIDDEN!>l1@<!> l2@{
         {
             <!NOT_A_FUNCTION_LABEL!>return@l1<!>
         }