End-to-end tests: Add CDK feature flags

Currently, the end-to-end tests create a CDK app without any feature flags set.

We should update the `tests/end-to-end/app-boilerplate-files/` for each language to include a context file with the latest default feature flags of a new CDK app. This should be a very simple matter of just adding the file, because the tests already use all files in each `boilerplate` directory when creating CDK apps.

Start by inspecting tests/end-to-end/app-boilerplate-files/ and its language-specific boilerplate directories. Compare each directory with the files used to create CDK apps, then identify the current default feature flags for a new CDK app and add the corresponding context file. Done means the end-to-end apps are created with those flags for every language.

Written by the indexing model from the issue text.