JVM_IR KT-45103 optimize direct invoke for lambdas and callable refs

compiler/testData/codegen/box/constants/privateConst.kt

@@ -1,7 +1,7 @@
+fun <T> eval(fn: () -> T) = fn()
+
 private const val z = "OK";
 
 fun box(): String {
-    return {
-        z
-    }()
+    return eval { z }
 }