KT-14258 Optimize accesses to properties defined into companion

- Use direct access to property defined into companion object when
it is possible rather than always use an accessor to access the
property.
- Use direct access will speedup runtime performance.
- Avoid to generate useless accessors for companion properties.

Fix of https://youtrack.jetbrains.com/issue/KT-14258

compiler/testData/asJava/lightClasses/nullabilityAnnotations/ClassObjectField.java

@@ -10,8 +10,6 @@ public final class ClassObjectField {
         @org.jetbrains.annotations.Nullable
         public final java.lang.String getX() { /* compiled code */ }
 
-        private final java.lang.String getY() { /* compiled code */ }
-
         private Companion() { /* compiled code */ }
     }
 }