Refrain from doing split query when not necessary

Test Collection_projection_over_GroupBy_over_parameter runs the following LINQ query:

```c#
var validIds = new List { "L1 01", "L1 02" };

return AssertQuery(
async,
ss => ss.Set()
.Where(l1 => validIds.Contains(l1.Name))
.GroupBy(l => l.Date)
.Select(g => new { g.Key, Ids = g.Select(e => e.Id) }),
elementSorter: e => e.Key,
elementAsserter: (e, a) =>
{
AssertEqual(e.Key, a.Key);
AssertCollection(e.Ids, a.Ids);
});
```

This produces the following SQL with single query (ComplexNavigationsCollectionsQuerySqlServerTest):

```sql
SELECT [t].[Date], [t0].[Id]
FROM (
SELECT [l].[Date]
FROM [LevelOne] AS [l]
WHERE [l].[Name] IN (N'L1 01', N'L1 02')
GROUP BY [l].[Date]
) AS [t]
LEFT JOIN (
SELECT [l0].[Id], [l0].[Date]
FROM [LevelOne] AS [l0]
WHERE [l0].[Name] IN (N'L1 01', N'L1 02')
) AS [t0] ON [t].[Date] = [t0].[Date]
ORDER BY [t].[Date]
```

And the following two queries with split query (ComplexNavigationsCollectionsSplitQuerySqlServerTest):

```sql
SELECT [l].[Date]
FROM [LevelOne] AS [l]
WHERE [l].[Name] IN (N'L1 01', N'L1 02')
GROUP BY [l].[Date]
ORDER BY [l].[Date];

SELECT [t0].[Id], [t].[Date]
FROM (
SELECT [l].[Date]
FROM [LevelOne] AS [l]
WHERE [l].[Name] IN (N'L1 01', N'L1 02')
GROUP BY [l].[Date]
) AS [t]
INNER JOIN (
SELECT [l0].[Id], [l0].[Date]
FROM [LevelOne] AS [l0]
WHERE [l0].[Name] IN (N'L1 01', N'L1 02')
) AS [t0] ON [t].[Date] = [t0].[Date]
ORDER BY [t].[Date];
```

There doesn't seem to be a good reason to actually split the query. I'm not sure what the characteristics of this scenario are, but we should investigate if there are other scenarios where we're needlessly doing split query.