Fix test in Debug

Fix test failure when running in Debug instead of Release caused by `Microsoft.VisualStudio.TestPlatform.TestHost.DebugAssertException` when `Debug.Assert()` fires.

src/Polly.Core/Utils/DisposeHelper.cs

@@ -32,9 +32,9 @@ public static async ValueTask TryDisposeSafeAsync<T>(T value, bool isSynchronous
                 }
             }
         }
-        catch (Exception e)
+        catch (Exception)
         {
-            Debug.Assert(false, e.ToString());
+            // Swallow any exception
         }
     }
 }