JS: create new common directory for all generated tests, migrate several tests there

js/js.translator/testData/box/inline/vararg.kt

@@ -0,0 +1,36 @@
+package foo
+
+
+// CHECK_CONTAINS_NO_CALLS: test1
+// CHECK_CONTAINS_NO_CALLS: test2
+// CHECK_CONTAINS_NO_CALLS: test3 except=slice
+
+internal inline fun concat(vararg strings: String): String {
+    var result = ""
+
+    for (string in strings) {
+        result += string
+    }
+
+    return result
+}
+
+internal fun test1(): String {
+    return concat()
+}
+
+internal fun test2(): String {
+    return concat("a", "b", "c")
+}
+
+internal fun test3(list: Array<String>): String {
+    return concat(*list)
+}
+
+fun box(): String {
+    assertEquals("", test1())
+    assertEquals("abc", test2())
+    assertEquals("abcd", test3(arrayOf("a", "b", "c", "d")))
+
+    return "OK"
+}