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/staticMethod.kt

@@ -13,6 +13,6 @@ class A {
 
 fun box(): String {
     val args = arrayOf("Fail")
-    (A::main)(args)
+    (A::main).let { it(args) }
     return args[0]
 }