Tests failing because of different locales

[cincuranet]

Follow-up from #14889. The failing tests on Czech locale are these.

DTO_complex_distinct_orderby(isAsync: False)
DTO_complex_distinct_orderby(isAsync: True)
DTO_complex_orderby(isAsync: False)
DTO_complex_orderby(isAsync: True)
OrderBy_Join(isAsync: True)
OrderBy_Join(isAsync: False)
OrderBy_Take_Last_gives_correct_result(isAsync: False)
OrderBy_Take_Last_gives_correct_result(isAsync: True)
OrderBy_Dto_projection_skip_take(isAsync: True)
OrderBy_Dto_projection_skip_take(isAsync: False)
DTO_member_distinct_orderby(isAsync: False)
DTO_member_distinct_orderby(isAsync: True)

Signalled by @lauxjpn in #20640: BuiltInDataTypesTestBase.Object_to_string_conversion

[smitpatel]

Customer.City column has certain characters with Unicode and difference in first letter's casing which gives ordering differences.

[ajcvickers]

@smitpatel Is the ordering happening because of client eval in the queries, or only on the L2O execution that we use to verify the results?

[smitpatel]

City has different orderings on server side too between different providers.

[roji]

@cincuranet can you confirm whether you're seeing culture-related failures on one of the built-in providers (SQL Server/Sqlclient) or only on Firebird? Can you post an exception or assertion failure, on, say, OrderByJoin?

[roji]

@cincuranet ping

[cincuranet]

Haven't had time to run the SQL Server tests yet. But it's on my list, don't worry.

[cincuranet]

@roji Yes, even the built-in providers are failing. I tried it quick'n'dirty in #15176. Which failed here, but when reverted went fine here.

[smitpatel]

The issue is L2O is using local culture but server never does. Perhaps we should specify invariant culture orderings for L2O query validation.