#3939 shows that graphql.schema.GraphQLTypeUtil#unwrapNonNull is called a lot

This is a smidge faster since it does less checking of values

cpu hot spots to look into

1.5% - 1,190 ms - 7,119,736 hot spot inv. graphql.schema.GraphQLTypeUtil.unwrapNonNull

1.5% - 1,209 ms - 7,088,722 hot spot inv. graphql.execution.ExecutionStepInfo.getUnwrappedNonNullType

So graphql.execution.ExecutionStepInfo.getUnwrappedNonNullType calls graphql.schema.GraphQLTypeUtil.unwrapNonNull so we can discount it but this makes the underlying method a smidge quicker

Also we save a extra loop in the lookup because double non null wrapping cant happen and hence we can save the loop checking