Fix for static - write NEED_SYNTHETIC flag on original descriptor

compiler/testData/codegen/box/classes/classObjectWithPrivateGenericMember.kt

@@ -0,0 +1,15 @@
+class C() {
+    class object {
+        private fun <T> create() = C()
+    }
+
+    class ZZZ {
+        val c = C.create<String>()
+    }
+}
+
+fun box(): String {
+    C.ZZZ().c
+    return "OK"
+}
+