FIR: Fix label/receiver for lambda within infix calls

While this fix only changes label name, it's important for proper
lambda resolution because receiver is set for a lambda
only in presence of a label

This commit fixes a lot of checkType calls in diagnostic tests

compiler/testData/codegen/box/labels/infixCallLabelling.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun test(x: Int): Int {
     x myMap {
         return@myMap
@@ -22,4 +21,4 @@ fun box(): String {
     myMap(0)
 
     return "OK"
-}
+}