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/callableReference/function/local/simpleWithArg.kt

@@ -1,4 +1,4 @@
 fun box(): String {
     fun foo(s: String) = s
-    return (::foo)("OK")
+    return (::foo).let { it("OK") }
 }