JS: move more test to box tests

js/js.translator/testData/box/reified/isChar.kt

@@ -0,0 +1,15 @@
+package foo
+
+// CHECK_NOT_CALLED: isInstance
+
+fun box(): String {
+    assertEquals(true, isInstance<Char>('c'))
+    assertEquals(false, isInstance<Char>(""))
+    assertEquals(false, isInstance<Char>("cc"))
+
+    assertEquals(true, isInstance<Char?>('c'), "isInstance<Char?>('c')")
+    assertEquals(true, isInstance<Char?>(null), "isInstance<Char?>(null)")
+    assertEquals(false, isInstance<Char?>("cc"), "isInstance<Char?>(\"cc\")")
+
+    return "OK"
+}