fix(KT-40236): compute JsName from overridden symbols.

js/js.translator/testData/box/propertyOverride/externalPropertyOverride.kt

@@ -0,0 +1,33 @@
+external interface A {
+    @JsName("__name")
+    val name: String
+
+    @JsName("bar")
+    fun foo(): String
+}
+
+external class B: A {
+    override val name: String
+    override fun foo(): String
+}
+
+fun box(): String {
+    val c = js("{ __name: 'Frodo', bar: function() { return 'Baggins' } }")
+
+    val a: A = c
+    val b: B = c
+
+    assertEquals(a.name, "Frodo")
+    assertEquals(a.asDynamic().__name, "Frodo")
+
+    assertEquals(b.name, "Frodo")
+    assertEquals(b.asDynamic().__name, "Frodo")
+
+    assertEquals(a.foo(), "Baggins")
+    assertEquals(a.asDynamic().bar(), "Baggins")
+
+    assertEquals(b.foo(), "Baggins")
+    assertEquals(b.asDynamic().bar(), "Baggins")
+
+    return "OK"
+}