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/multiDecl/forRange/int/MultiDeclForComponentExtensionsValCaptured.kt

@@ -4,7 +4,7 @@ operator fun Int.component2() = this + 2
 fun doTest(): String {
     var s = ""
     for ((a, b) in 0..2) {
-      s += {"$a:$b;"}()
+      s += {"$a:$b;"}.let { it() }
     }
     return s
 }