[JS IR] Fix name clash between class members defined on prototype

- Fixes [KT-33327]

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

@@ -1,6 +1,3 @@
-// Name clashes
-// IGNORE_BACKEND: JS_IR
-
 // EXPECTED_REACHABLE_NODES: 1295
 package foo
 

js/js.translator/testData/box/propertyAccess/publicNameClash.kt

@@ -0,0 +1,27 @@
+// EXPECTED_REACHABLE_NODES: 1284
+
+// KT-33327
+
+class C {
+    var foo: String = "FAIL1"
+
+    fun foo(foo: String): C {
+        this.foo = foo
+        return this
+    }
+
+    @JsName("_bar")
+    var bar: String = "FAIL2"
+
+    fun bar(bar: String): C {
+        this.bar = bar
+        return this
+    }
+}
+
+fun box(): String {
+    val c = C()
+    c.foo("O").bar("K")
+
+    return c.foo + c.bar
+}