fixup! Support evaluation of Random.Next and NextDouble on db side

Remove invalid floor registration for decimal input: it converts
it to integer, which breaks with an invalid cast
NHibernate.Test.NHSpecificTest.GH0831.ByCodeFixture.CanHandleFloor
using IQuery.List<Decimal>. (Well, it would also be broken with a
non-casting floor, due to SQLite having a broken decimal support.
But it is still invalid as floor should not change the value type.)

This causes Random.Next to be unsupported for SQLite. Random.Double
stays supported.

Author: fredericDelaporte

src/NHibernate/Dialect/SQLiteDialect.cs

@@ -117,15 +117,6 @@ protected virtual void RegisterFunctions()
 				new SQLFunctionTemplate(
 					NHibernateUtil.Double,
 					"(cast(random() as real) / 4611686018427387904 / 4 + 0.5)"));
-
-			// With SQLite, casting to int truncates, so for positive values a simple cast allows to emulate floor.
-			// But for negative values, this is a bit more complicated. Taken from
-			// https://stackoverflow.com/q/7129249/1178314#comment8545746_7129253
-			RegisterFunction(
-				"floor",
-				new SQLFunctionTemplate(
-					NHibernateUtil.Double,
-					"case when ?1 >= 0 then cast(?1 as int) when cast(?1 as int) = ?1 then cast(?1 as int) else cast(?1 - 1.0 as int) end"));
 		}
 
 		#region private static readonly string[] DialectKeywords = { ... }