System.Net.*.Tests are unstable or slow/long-running on a S.P.CoreLib checked runtime

[safern]

We're disabling some System.Net.*.Tests assemblies when running on a checked runtime in: #261. However we should investigate what can we do to enable these tests there.

I.e System.Net.Sockets.Tests would be a really would candidate for runtime testing and stress testing.

cc: @BruceForstall @jkotas @stephentoub

[davidsh]

@wfurt

[ViktorHofer]

Do we know why especially the networking tests are so slow on a checked runtime?

[davidsh]

What is a "checked" runtime? I know what Debug vs. Release is. How does "checked" related to that?

[BruceForstall]

Checked is the same as Debug (e.g., asserts enabled), but with the C++ compiler optimization enabled (so native code runs much faster).

[wfurt]

It would be great to get more specific instructions how to know produce one and to know if test run is checked. I always assumed that checked would be slower than Debug but it seems like it may not.
Lot of networking code (product & tests) depends on timing. That is different from let say data structure tests. There are some constants for test and AFAIK we already adjusted some for ARM runs. We could possibly do that for checked builds if needed. But first we need to be able to reproduce it local and take a look.

[karelz]

Any update on this? @BruceForstall @ViktorHofer @safern