Move checking for cancelled token into try-catch to guarantee that UpdateSessionState() is invoked (in finally)

(cherry picked from commit 3befe19)

Author: nerzhulart

Mono.Debugging.Soft/SoftDebuggerAdaptor.cs

@@ -2231,11 +2231,11 @@ protected override Task<OperationResult<Value>> InvokeAsyncImpl ()
 				}
 				var tcs = new TaskCompletionSource<OperationResult<Value>> ();
 				invokeAsyncResult = (IInvokeAsyncResult)obj.BeginInvokeMethod (ctx.Thread, function, args, optionsToInvoke, ar => {
-					if (Token.IsCancellationRequested) {
-						tcs.SetCanceled ();
-						return;
-					}
 					try {
+						if (Token.IsCancellationRequested) {
+							tcs.SetCanceled ();
+							return;
+						}
 						var endInvokeResult = obj.EndInvokeMethodWithResult (ar);
 						tcs.SetResult (new SoftOperationResult (endInvokeResult.Result, false, endInvokeResult.OutArgs));
 					}