Update bug links

src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenAsyncTests.cs

@@ -1916,7 +1916,7 @@ static void Main()
             CompileAndVerify(source, "0");
         }
 
-        [Fact(Skip = "1089468")]
+        [Fact(Skip = "https://github.com/dotnet/roslyn/issues/4300")]
         public void Return07_2()
         {
             var source = @"

src/Compilers/Core/VBCSCompilerTests/CompilerServerApiTest.cs

@@ -274,7 +274,7 @@ public async Task FailedConnectionShouldCreateFailedConnectionData()
         /// <summary>
         /// Ensure server respects keep alive and shuts down after processing a single connection.
         /// </summary>
-        [Fact(Skip = "DevDiv 1095079")]
+        [Fact(Skip = "https://github.com/dotnet/roslyn/issues/4301")]
         public async Task KeepAliveAfterSingleConnection()
         {
             var keepAlive = TimeSpan.FromSeconds(1);
@@ -297,7 +297,7 @@ public async Task KeepAliveAfterSingleConnection()
         /// <summary>
         /// Ensure server respects keep alive and shuts down after processing multiple connections.
         /// </summary>
-        [Fact(Skip = "DevDiv 1095079")]
+        [Fact(Skip = "https://github.com/dotnet/roslyn/issues/4301")]
         public async Task KeepAliveAfterMultipleConnection()
         {
             var keepAlive = TimeSpan.FromSeconds(1);
@@ -323,7 +323,7 @@ public async Task KeepAliveAfterMultipleConnection()
         /// <summary>
         /// Ensure server respects keep alive and shuts down after processing simultaneous connections.
         /// </summary>
-        [Fact(Skip = "DevDiv 1095079")]
+        [Fact(Skip = "https://github.com/dotnet/roslyn/issues/4301")]
         public async Task KeepAliveAfterSimultaneousConnection()
         {
             var keepAlive = TimeSpan.FromSeconds(1);
@@ -353,7 +353,7 @@ public async Task KeepAliveAfterSimultaneousConnection()
             Assert.True((DateTime.Now - listener.LastProcessedTime.Value) > keepAlive);
         }
 
-        [Fact(Skip = "DevDiv 1095079"), WorkItem(1095079)]
+        [Fact(Skip = "https://github.com/dotnet/roslyn/issues/4301")]
         public async Task FirstClientCanOverrideDefaultTimeout()
         {
             var cts = new CancellationTokenSource();