Remove newKeyInstance() and newValueInstance() as more confusing than helpful

src/main/java/net/openhft/chronicle/map/VanillaChronicleMap.java

@@ -142,18 +142,6 @@ public class VanillaChronicleMap<K, V, R>
         return (V) value;
     }
 
-    @Override
-    public V newValueInstance() {
-        if (vClass == CharSequence.class || vClass == StringBuilder.class)
-            return (V) new StringBuilder();
-        return newInstance(vClass, false);
-    }
-
-    @Override
-    public K newKeyInstance() {
-        return newInstance(kClass, true);
-    }
-
     @Override
     public Class<K> keyClass() {
         return kClass;