fold reference to SslContextHandle to prevent crashes

src/libraries/Common/src/Interop/Unix/System.Security.Cryptography.Native/Interop.OpenSsl.cs

@@ -409,6 +409,9 @@ internal static SafeSslHandle AllocateSslHandle(SafeFreeSslCredentials credentia
                     if (cacheSslContext && !string.IsNullOrEmpty(punyCode))
                     {
                         sslCtxHandle.TrySetSession(sslHandle, punyCode);
+                        bool ignored = false;   // DangerousAddRef will throw on failure
+                        sslCtxHandle.DangerousAddRef(ref ignored);
+                        sslHandle.SslContextHandle = sslCtxHandle;
                     }
 
                     // relevant to TLS 1.3 only: if user supplied a client cert or cert callback,

src/libraries/Common/src/Interop/Unix/System.Security.Cryptography.Native/Interop.Ssl.cs

@@ -335,6 +335,7 @@ internal sealed class SafeSslHandle : SafeHandle
         private bool _handshakeCompleted;
 
         public GCHandle AlpnHandle;
+        public SafeSslContextHandle? SslContextHandle;
 
         public bool IsServer
         {
@@ -432,6 +433,8 @@ protected override bool ReleaseHandle()
                 Disconnect();
             }
 
+            SslContextHandle?.DangerousRelease();
+
             IntPtr h = handle;
             SetHandle(IntPtr.Zero);
             Interop.Ssl.SslDestroy(h); // will free the handles underlying _readBio and _writeBio