[wasm] Re-enable some tests in the System.Net.WebSockets.Tests namesp…

…ace (#40004)

There is no repro for dotnet/runtime#38807 at the moment so the related tests have been enabled.
Two tests have been disabled due to PNSE (see dotnet/runtime#39346).

Fixes: dotnet/runtime#38807 

The test run result: `Tests run: 177, Errors: 0, Failures: 0, Skipped: 0.`

tests/WebSocketProtocolTests.cs

@@ -6,7 +6,6 @@
 
 namespace System.Net.WebSockets.Tests
 {
- [ActiveIssue("https://github.com/dotnet/runtime/issues/38807", TestPlatforms.Browser)]
  public sealed class WebSocketProtocolCreateTests : WebSocketCreateTest
  {
  protected override WebSocket CreateFromStream(Stream stream, bool isServer, string subProtocol, TimeSpan keepAliveInterval) =>