JS: move expressions test to box tests

js/js.translator/testData/box/expression/equals/customEqualsMethod.kt

@@ -0,0 +1,24 @@
+package foo
+
+class Foo(val name: String) {
+    override fun equals(other: Any?): Boolean {
+        if (other !is Foo) {
+            return false
+        }
+        return this.name == other.name
+    }
+}
+
+fun callEqualsMethod(v1: Foo?, v2: Foo?): Boolean {
+    return v1 == v2
+}
+
+fun box(): String {
+    val a = Foo("abc")
+    val b = Foo("abc")
+    val c = Foo("def")
+
+    if (!callEqualsMethod(a, b)) return "fail1"
+    if (callEqualsMethod(a, c)) return "fail2"
+    return "OK"
+}