Use IN instead of EXISTS in more places

[roji]

• First, this optimizes to use IN syntax instead of EXISTS for entity equality/containment e.g. (context.Blogs.Where(b => ctx.BlogsDetails.Contains(b.Details))) - when the entity has a non-composite key (composite keys are still translate via EXISTS). This improves on #30955, which already switched most queries from IN to EXISTS where possible, but not for entity equality/containment.
• It then leverages this and switches to using Contains in ExecuteDelete. This form comes into use for complex querying which cannot be directly translated to DELETE; we then add a WHERE clause that checks whether the row's PK is in a subquery containing the complex conditions.
• Note that ExecuteUpdate generated an inner join instead of IN/EXISTS. This is because unlike with delete, update supports arbitrary projections (e.g. into anonymous types), and that's tricky to get working with IN/EXISTS. The inner join approach should be just as efficient - if a tad uglier - so I'm leaving as-is for now.

Closes #31386