Improve string comparison

Author: alex-kulakov

Orm/Xtensive.Orm/Orm/Providers/SqlCompiler.Helpers.cs

@@ -181,10 +181,10 @@ private static bool IsColumnStub(SqlColumn column)
     private static bool IsTypeIdColumn(SqlColumn column)
     {
       if (column is SqlUserColumn)
-        return (StringComparer.InvariantCultureIgnoreCase.Compare(column.Name, "TypeId") == 0);
+        return string.Equals(column.Name, "TypeId", StringComparison.OrdinalIgnoreCase);
       var cRef = column as SqlColumnRef;
       if (!ReferenceEquals(null, cRef))
-        return (StringComparer.InvariantCultureIgnoreCase.Compare(column.Name, "TypeId") == 0);
+        return string.Equals(cRef.Name, "TypeId", StringComparison.OrdinalIgnoreCase);
       return false;
     }