added test for main function

testData/ast/function/method/main.jav

@@ -0,0 +1 @@
+public static void main(String[] args) {}

testData/ast/function/method/main.kt

@@ -0,0 +1,4 @@
+class object {
+open public fun main(args : Array<String?>?) : Unit {
+}
+}