efd71291 added on erp5_invoicing a test dependency on erp5_advanced_invoicing.
However, testRule for example uses erp5_invoicing but not erp5_advanced_invoicing
so this would not work.

Moreover, erp5_{simplified,advanced}_invoicing enhance erp5_invoicing by providing
a container for Invoice Line so to match real world use cases it is better to
have two CodingStyle tests: one checking erp5_invoicing+erp5_simplified_invoicing
and the other one erp5_invoicing+erp5_advanced_invoicing.

Also, fix CodingStyle issues on erp5_advanced_invoicing.