string.StartsWith/EndsWith do not respect StringComparison arg.

This bug hits atleast Firebird and Sqlite providers.

		[Test, Combinatorial]
		public void SearchStringTest(
			[IncludeDataSources(TestProvName.AllSQLite, TestProvName.AllFirebird)] string context, 
			[Values(nameof(string.StartsWith), nameof(string.EndsWith))] string methodName,
			[Values]bool ignoreCase)
		{
			var stringComparison = ignoreCase ? StringComparison.OrdinalIgnoreCase : StringComparison.Ordinal;
			Expression<Func<Model.Person, bool>> GetPredicate(string param) => methodName switch
			{
				nameof(string.StartsWith) => (Model.Person p) => p.LastName.StartsWith(param, stringComparison),
				nameof(string.EndsWith) => (Model.Person p) => p.LastName.EndsWith(param, stringComparison),				
				_ => throw new ArgumentException("Unknown method name " + methodName)
			};

			using (var db = GetDataContext(context))
			{
				Assert.IsTrue(db.Person.Any(GetPredicate("Pupkin")));
				Assert.AreEqual(ignoreCase, db.Person.Any(GetPredicate("pupkin")));
			}			
		}

Also there is FB specific issue in FirebirdSqlOptimizer.ConvertSearchStringPredicate. “starting with” is case-sensitive, but linq2db use it in “ignorecase” branch

Environment details

linq2db version: 3.3 Database Server: Firebird

[sdanyliv]

Don’t worry I know all places which I have to fix. This is one of them.

[jack128]

Well, FB doesnt have any special support for non-case sensitive search. So i’d use lower function. "lower(Field) starting with @p"