disable some racy RemotingSpecs [Akka.Remote.Tests] (#3839)
disable some racy RemotingSpecs [Akka.Remote.Tests] (#3839)

* force RemotingSpecs to run sequentially

* marked two particularly bad specs as skipped

* Removed XUnit collection attribute

Don't need a collection anymore now that the entire test is run sequentially

simonlaroche/akka.net,simonlaroche/akka.net