FIR checker: skip error named reference if receiver is unresolved

Currently, FIR reports errors caused by previous resolution failure. For
example with unresolved `a` and `b` in code `a.b`, both `a` and `b` are
highlighted. FE1.0 only highlights `a` since it's the root cause. This
change applies this heuristics when reporting FirDiagnostics.

compiler/testData/diagnostics/tests/classObjects/InnerClassAccessThroughClassObject.fir.kt

@@ -43,7 +43,7 @@ fun f() {
     A.Obj
     A.Companion.Obj2
     A.<!UNRESOLVED_REFERENCE!>Obj2<!>
-    A.<!UNRESOLVED_REFERENCE!>Obj2<!>.<!UNRESOLVED_REFERENCE!>c<!>
+    A.<!UNRESOLVED_REFERENCE!>Obj2<!>.c
     A.<!UNRESOLVED_REFERENCE!>Nested2<!>
 
     O.O