JVM IR: Avoid direct invokes in callable reference tests

Due to the direct invoke optimization, most callable reference tests
were not generating callable references/lambdas.

compiler/testData/codegen/box/delegatedProperty/local/kt16864.kt

@@ -8,5 +8,5 @@ fun box(): String {
         object {
             val keys = key
         }.keys
-    } ()
+    }.let { it() }
 }