Allow specify property value without lambda in ExecuteUpdate

[roji]

Fixes #28968

Description

This is a non-breaking tweak to a new API introduced in EF7. It allows a simpler form to be used for ExecuteUpdate. Specifcally,

.SetProperty(p => p.Name, "Shay")

can be used instead of

.SetProperty(p => p.Name, _ => "Shay")

There may be many calls to SetProperty and setting to a value that does not depend on any other values in the entity is a very common case.

Customer impact

Shorter, more readable code for a frequently used common case.

How found

Customer suggestion.

Regression

No. New API, and this is non-breaking for existing use of that API in RC1.

Testing

New tests added.

Risk

Low; non-breaking tweak to new API.

---

@smitpatel as discussed offline. Added various closure tests, funcletizer seems to be humming along with 100% efficiency.

AFAICT, switching from Expression to regular non-Expression doesn't seem to create particular difficulties for dynamic expression construction. Here's a sample:

await ctx.Blogs.ExecuteUpdateAsync(sp => sp
    .SetProperty(b => b.Name, "Hello"));

// Same thing dynamically:
var setPropertyMethodInfo = typeof(SetPropertyCalls<>).MakeGenericType(typeof(Blog))
    .GetMethods()
    .Single(m => m.Name == nameof(SetPropertyCalls<Blog>.SetProperty)
                 && m.GetParameters()[0].ParameterType.IsGenericType
                 && m.GetParameters()[0].ParameterType.GetGenericTypeDefinition() == typeof(Func<,>)
                 && !m.GetParameters()[1].ParameterType.IsGenericType)
    .MakeGenericMethod(typeof(string));

var setPropertyCallsParam = Expression.Parameter(typeof(SetPropertyCalls<Blog>), "sp");
var blogParam1 = Expression.Parameter(typeof(Blog), "b");

Expression<Func<SetPropertyCalls<Blog>, SetPropertyCalls<Blog>>> setProperties =
    Expression.Lambda<Func<SetPropertyCalls<Blog>, SetPropertyCalls<Blog>>>(
        Expression.Call(
            setPropertyCallsParam,
            setPropertyMethodInfo,
            Expression.Lambda<Func<Blog, string>>(Expression.Property(blogParam1, nameof(Blog.Name)), blogParam1),
            Expression.Constant("Hello")),
        setPropertyCallsParam);

await ctx.Blogs.ExecuteUpdateAsync(setProperties);

What do you think?

Closes #28968

[smitpatel]

?

[roji]

Slipped in, removing.

[ajcvickers]

@roji Approved by Tactics. Please merge ASAP.