Make BlackBox tests for Java 9 generated

compiler/testData/codegen/java9/box/concatDynamicWithInline.kt

@@ -18,8 +18,4 @@ fun box(): String {
 
     val result2 = test { it + "_" }
     return if (result2 != "12_3456_789_10")  "fail 2: $result2" else "OK"
-}
-
-fun main() {
-    box().let { if (it != "OK") throw AssertionError(it) }
 }