Test Ionic application to showcase tree-shaking issue with Popovers and their backdrop

Steps to reproduce

1. npm install
2. npm install -g serve
3. npm run build
4. serve -s build
5. Click the button to open the Popover, notice that no backdrop appears, and that the popover cannot be closed by clicking outside of it.

When running the application using npm run start, everything works as expected.

There is a temp-fix branch that contains one change: a console.log(IonBackdrop) statement, which prevents the backdrop component from being marked as dead code. On this branch, the popover works as expected.