[K/JS] Rework main function call to support it in per-file

js/js.translator/testData/box/esModules/main/twoMains.kt

@@ -0,0 +1,18 @@
+// EXPECTED_REACHABLE_NODES: 1281
+// ES_MODULES
+// CALL_MAIN
+
+var o: String = "fail O"
+var k: String = "K"
+
+fun main() {
+    k = "fail K"
+}
+
+fun main(args: Array<String>) {
+    if (args.size != 0) error("Fail")
+
+    o = "O"
+}
+
+fun box() = o + k