Handle GraphQL Non-null wrappers in tests and implementation

[shalarewicz]

GraphQLNonNull types can wrap any GraphQLInputType. We should add tests and update buildTypeWeights and complexity analysis to ensure both incoming queries and schemas including non null types are accounted for and successfully parsed.

Per the GraphQL type def files GraphQLInputType can consist of the following types. Note the level of nesting that can occur.

GraphQLInputType = 
  | GraphQLScalarType
  | GraphQLEnumType
  | GraphQLInputObjectType
  | GraphQLList<GraphQLInputType>
  | GraphQLNonNull<
      | GraphQLScalarType
      | GraphQLEnumType
      | GraphQLInputObjectType
      | GraphQLList<GraphQLInputType>
 >;

[shalarewicz]

Confirm success by enabling the following tests:

• buildTypeWeights Not null operator (!) is used
• weightFunction the list is defined with non-null operators (!)