Extra test should be added for Dictionary

[benaadams]

This code should work

var d = new Dictionary<string,string>();
d.Add("a", "b");
d.Add("c", "d");
foreach (var e in d)
{
    if (d.Remove(e.Key + "Sibling")) break;
}

From dotnet/coreclr#17196 (comment)

/cc @danmosemsft Just so it doesn't fall off the radar

[danmoseley]

@maryamariyan mind adding this?

[maryamariyan]

@danmosemsft sure, thanks

[benaadams]

For background; I changed Remove to always increment version rather than to do it only when an item was removed which would mean that example would throw an exception about the enumerator no longer being valid (then reverted it) dotnet/coreclr#17196 (comment)