Always create descriptors for class object psi element in lazy resolve

KT-4397 Exception: @NotNull method org/jetbrains/jet/lang/resolve/lazy/ResolveSession.getClassDescriptor must not return null

 #KT-4397 Fixed

idea/testData/codeInsight/lineMarker/ClassObjectInStaticNestedClass.kt

@@ -0,0 +1,12 @@
+trait <lineMarker></lineMarker>TestTrait {
+    fun <lineMarker></lineMarker>test()
+}
+
+class A {
+    class B {
+        class object : TestTrait { // TODO: No line marker
+            override fun <lineMarker descr="<b>internal</b> <b>open</b> <b>fun</b> test(): jet.Unit <i>defined in</i> A.B.&lt;class-object-for-B&gt;<br/>implements<br/><b>internal</b> <b>abstract</b> <b>fun</b> test(): jet.Unit <i>defined in</i> TestTrait"></lineMarker>test() {
+            }
+        }
+    }
+}