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

js/js.translator/testData/box/char/charConversions.kt

@@ -0,0 +1,14 @@
+package foo
+
+fun box(): String {
+
+    assertEquals('A', 'A'.toChar(), "toChar")
+    assertEquals(65, 'A'.toInt(), "toInt")
+    assertEquals(65.toShort(), 'A'.toShort(), "toShort")
+    assertEquals(65.toByte(), 'A'.toByte(), "toByte")
+    assertEquals(65.0, 'A'.toDouble(), "toDouble")
+    assertEquals(65.0f, 'A'.toFloat(), "toFloat")
+    assertEquals(65L, 'A'.toLong(), "toLong")
+
+    return "OK"
+}