Enum entries: add new tests with language feature ON & fix checker

compiler/testData/diagnostics/tests/enum/entries/entriesPropertyInCompanionClashOn.fir.kt

@@ -0,0 +1,28 @@
+// !LANGUAGE: +EnumEntries
+// WITH_STDLIB
+
+enum class A {
+    ;
+
+    companion object {
+        val entries = 0
+    }
+}
+
+fun test() {
+    A.<!OPT_IN_USAGE_ERROR!>entries<!>
+    A.Companion.entries
+
+    <!NEW_INFERENCE_NO_INFORMATION_FOR_PARAMETER!>with<!>(A) {
+        entries
+        this.entries
+        <!UNRESOLVED_REFERENCE!>values<!>() // to be sure that we don't resolve into synthetic 'values'
+    }
+
+    with(A.Companion) {
+        entries
+    }
+
+    val aCompanion = A.Companion
+    aCompanion.entries
+}