[IR] update testdata: better support for IrCall

compiler/testData/ir/irText/expressions/variableAsFunctionCall.kt.txt

@@ -14,7 +14,7 @@ fun test2(f: @ExtensionFunctionType Function1<String, Unit>) {
 }
 
 fun test3(): String {
-  return k($receiver = "hello").invoke()
+  return "hello".k().invoke()
 }
 
 fun test4(ns: String?): String? {
@@ -23,7 +23,7 @@ fun test4(ns: String?): String? {
       val tmp0_safe_receiver: String? = ns
       when {
         EQEQ(arg0 = tmp0_safe_receiver, arg1 = null) -> null
-        true -> k($receiver = tmp0_safe_receiver)
+        true -> tmp0_safe_receiver.k()
       }
     }
     when {