Fine-tuning for non-null FeatureParams

See MicrosoftDocs/typography-issues#439

and
https://docs.microsoft.com/en-us/typography/opentype/spec/featuretags

and "Registered features, definitions and implementations", a-e and p-t:

https://docs.microsoft.com/en-us/typography/opentype/spec/features_ae
https://docs.microsoft.com/en-us/typography/opentype/spec/features_pt

OTFontFileVal/OTLVal.cs

@@ -581,9 +581,13 @@ public bool Validate(Validator v, string sIdentity, OTTable table)
         {
             bool bRet = true;
 
-            if (sIdentity.EndsWith("(size), FeatureTable"))
+            if (sIdentity.EndsWith("(size), FeatureTable") ||
+                sIdentity.Contains("(cv") ||
+                sIdentity.Contains("(ss0") || // avoid matching "ssty"
+                sIdentity.Contains("(ss1") ||
+                sIdentity.Contains("(ss2"))
             {
-                // The "size" feature is special in having non-null FeatureParams
+                // The "size", "cvNN" and "ssNN" features are special in having non-null FeatureParams
 
                 // TODO
             }