Remove RemoteControl workaround (#78907)

Author: CyrusNajmabadi

src/VisualStudio/Core/Def/Storage/FileDownloader.cs

@@ -30,40 +30,9 @@ public IFileDownloader CreateClient(string hostId, string serverPath, int pollin
     private FileDownloader(RemoteControlClient client)
         => _client = client;
 
-#if NET
-
-    /// <summary>
-    /// The netcore version of <see cref="RemoteControlClient"/> doesn't support ReturnStale.  It will download the file
-    /// (on a separate thread), but then not cache it because it doesn't have access to the normal IE component that
-    /// does proper header reading/caching.  Then, when we call in to read the file, we get nothing back, since nothing
-    /// was cached.
-    /// <para/> The temporary solution to this is to force the download to happen.  This is not ideal as we will no
-    /// longer be respecting the server "Cache-Control:Max-Age" header.  Which means we'll continually download the
-    /// files, even if not needed (since the server says to use the local value).  This is not great, but is not
-    /// terrible either.  First, we will only download the full DB file <em>once</em>, when it is actually missing on
-    /// the user's machine.  From that point on, we'll only be querying the server for the delta-patch file for the DB
-    /// version we have locally.  The vast majority of the time that is a tiny document of the form <c><![CDATA[<Patch
-    /// upToDate="true" FileVersion="105" ChangesetId="1CBE1453" />]]></c> (around 70 bytes) which simply tells the user
-    /// they are up to date.  Only about once every three months will they actually download a large patch file.  Also,
-    /// this patch download will only happen once a day tops (as that is our cadence for checking if there are new index
-    /// versions out).
-    /// <para/> https://github.com/dotnet/roslyn/issues/71014 tracks this issue.  Once RemoteControlClient is updated to
-    /// support this again, we can remove this specialized code for netcore.
-    /// </summary>
-    public async Task<Stream?> ReadFileAsync()
-        // Note: we try .ReturnStale first so this will automatically light up once they fix their issue, without 
-        // us having to do anything on our end.  Once we do get around to making a change, we'll remove the 
-        // .ForceDownload part entirely.
-        => await _client.ReadFileAsync(BehaviorOnStale.ReturnStale).ConfigureAwait(false) ??
-           await _client.ReadFileAsync(BehaviorOnStale.ForceDownload).ConfigureAwait(false);
-
-#else
-
     public Task<Stream?> ReadFileAsync()
         => _client.ReadFileAsync(BehaviorOnStale.ReturnStale);
 
-#endif
-
     public void Dispose()
         => _client.Dispose();
 }