fix(cli): stack outputs aren't sorted (#10328)

When running `cdk deploy` the stack outputs to the terminal are currently returned in the same order as the `describe stacks` API call, which does not seem to provide a contract on ordering, per the [docs](https://docs.aws.amazon.com/AWSCloudFormation/latest/APIReference/API_Stack.html).

This change sorts the keys of the stack outputs before display, which is consistent with "outputs" tab in the AWS CloudFormation console.

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*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/aws-cdk/lib/cdk-toolkit.ts

@@ -206,7 +206,7 @@ export class CdkToolkit {
           stackOutputs[stack.stackName] = result.outputs;
         }
 
-        for (const name of Object.keys(result.outputs)) {
+        for (const name of Object.keys(result.outputs).sort()) {
           const value = result.outputs[name];
           print('%s.%s = %s', colors.cyan(stack.id), colors.cyan(name), colors.underline(colors.cyan(value)));
         }