Restore calls to CreateFatalHandshakeAlertToken on Android (#118765)

Author: rzikm

src/libraries/System.Net.Security/src/System/Net/Security/SslStreamPal.Android.cs

@@ -21,7 +21,11 @@ public static Exception GetException(SecurityStatusPal status)
 
         internal const bool StartMutualAuthAsAnonymous = false;
         internal const bool CanEncryptEmptyMessage = false;
-        internal const bool CanGenerateCustomAlerts = false;
+
+        // There is no API to generate custom alerts on Android, but the interop layer currently
+        // depends on SslStream calling HandshakeInternal one last time when tearing down the connection
+        // due to handshake failures.
+        internal const bool CanGenerateCustomAlerts = true;
 
         public static void VerifyPackageInfo()
         {
@@ -231,7 +235,6 @@ public static SecurityStatusPal ApplyAlertToken(
         {
             // There doesn't seem to be an exposed API for writing an alert.
             // The API seems to assume that all alerts are generated internally.
-            Debug.Assert(CanGenerateCustomAlerts);
             return new SecurityStatusPal(SecurityStatusPalErrorCode.OK);
         }