Correct non-NodaTime date/time type mappings when NodaTime is configured (#3214)

Fixes #3213

(cherry picked from commit dba77fd)

Author: roji

src/EFCore.PG/Query/ExpressionTranslators/Internal/NpgsqlDateTimeMemberTranslator.cs

@@ -27,8 +27,8 @@ public class NpgsqlDateTimeMemberTranslator : IMemberTranslator
     public NpgsqlDateTimeMemberTranslator(IRelationalTypeMappingSource typeMappingSource, NpgsqlSqlExpressionFactory sqlExpressionFactory)
     {
         _typeMappingSource = typeMappingSource;
-        _timestampMapping = typeMappingSource.FindMapping("timestamp without time zone")!;
-        _timestampTzMapping = typeMappingSource.FindMapping("timestamp with time zone")!;
+        _timestampMapping = typeMappingSource.FindMapping(typeof(DateTime), "timestamp without time zone")!;
+        _timestampTzMapping = typeMappingSource.FindMapping(typeof(DateTime), "timestamp with time zone")!;
         _sqlExpressionFactory = sqlExpressionFactory;
     }
 

src/EFCore.PG/Query/ExpressionTranslators/Internal/NpgsqlDateTimeMethodTranslator.cs

@@ -113,9 +113,9 @@ public NpgsqlDateTimeMethodTranslator(
     {
         _typeMappingSource = typeMappingSource;
         _sqlExpressionFactory = sqlExpressionFactory;
-        _timestampMapping = typeMappingSource.FindMapping("timestamp without time zone")!;
-        _timestampTzMapping = typeMappingSource.FindMapping("timestamp with time zone")!;
-        _intervalMapping = typeMappingSource.FindMapping("interval")!;
+        _timestampMapping = typeMappingSource.FindMapping(typeof(DateTime), "timestamp without time zone")!;
+        _timestampTzMapping = typeMappingSource.FindMapping(typeof(DateTime), "timestamp with time zone")!;
+        _intervalMapping = typeMappingSource.FindMapping(typeof(TimeSpan), "interval")!;
         _textMapping = typeMappingSource.FindMapping("text")!;
     }