Add missing used features to private fields tests (#2361)

test/language/statements/class/elements/private-field-is-visible-in-computed-properties.js

@@ -43,7 +43,7 @@ info: |
     3. If the binding for N in envRec is an uninitialized binding, throw a ReferenceError exception.
     ...
 
-features: [class-fields-private, class]
+features: [class-fields-private, class-fields-public, class]
 ---*/
 
 const self = this;

test/language/statements/class/elements/private-field-with-initialized-id-is-visible-in-computed-properties.js

@@ -63,7 +63,7 @@ info: |
     4. If entry is empty, throw a TypeError exception.
     5. Return entry.[[PrivateFieldValue]].
 
-features: [class-fields-private, class]
+features: [class-fields-private, class-fields-public, class]
 ---*/
 
 const self = this;