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/Unresolved.fir.kt

@@ -22,11 +22,11 @@ fun testUnresolved() {
         is String -> <!UNRESOLVED_REFERENCE!>a<!>
     }
 
-    <!UNRESOLVED_REFERENCE, UNRESOLVED_REFERENCE, UNRESOLVED_REFERENCE!>for (j in <!UNRESOLVED_REFERENCE!>collection<!>) {
+    <!UNRESOLVED_REFERENCE, UNRESOLVED_REFERENCE!>for (j in <!UNRESOLVED_REFERENCE!>collection<!>) {
        var i: Int = j
        i += 1
        foo1(j)
     }<!>
 }
 
-fun foo1(i: Int) {}
+fun foo1(i: Int) {}