C#: compiler-inserted calls (using, foreach, collection initializer) and functions handed to a parameter have no edge #1900

C# calls the compiler inserts, and calls through a function value handed to a parameter, have no edge, so impact / path miss the methods they run:

• using (var r = ...) / using var r = ... runs r.Dispose() at scope end;
• foreach (var x in c) runs c.GetEnumerator();
• a collection initializer new Bag { 1, { 2, 3 } } runs Add(...) per element;
• a lambda or method group passed as an argument (to a method, a constructor or a primary constructor) and then called there, directly or after being stored in a field;
• a lambda inside a collection initializer has no parameter types, so calls in its body are unresolved.

On the compiler-resolved call graph these were 100% missing before the fix on the projects that use them (up to 1,070 sites in one project); after it, 75–89% match exactly.

Fixed by #1896.