[Ada] AI12-0311 New checks for language-defined units

[Ada] AI12-0311 New checks for language-defined units

2020-06-10  Arnaud Charlet  <charlet@adacore.com>

gcc/ada/

	* snames.ads-tmpl (Name_Characters_Assertion_Check,
	Name_Containers_Assertion_Check,
	Name_Interfaces_Assertion_Check, Name_IO_Assertion_Check,
	Name_Numerics_Assertion_Check, Name_Strings_Assertion_Check,
	Name_System_Assertion_Check): New constants.
	* types.ads (Characters_Assertion_Check,
	Containers_Assertion_Check, Interfaces_Assertion_Check,
	IO_Assertion_Check, Numerics_Assertion_Check,
	Strings_Assertion_Check, System_Assertion_Check): New constants.
	(All_Checks): Update accordingly.