In light of #29926, that will change the path of `tsconfig.app.json`,
this commit switches from a hard-coded `tsconfig.app.json` path to
looking it up in `angular.json` (to be more future-proof).
PR Close#29989
Previously, the `build-with-ivy` script could be used to build the `aio`
project with Ivy (once it had been prepared with `ivy-ngcc`, etc.) and
then restored the configuration (e.g. `tsconfig.json`) to non-ivy mode.
As a result, it was not useful for running other commands (e.g. unit/e2e
tests) in Ivy mode.
This commit renames the script to `switch-to-ivy` and employs a
different model (similar to `ng-packages-installer`), where the project
is setup to run in Ivy mode and then all subsequent commands are
executed in that mode (until restored).
Since this is currently only used on CI, there is no automatic way to
switch back to non-ivy mode (but it could be implemented in the future
if needed).
Finally, the script now modifies `src/tsconfig.app/json` instead of
`tsconfig.json` to ensure that the `angularCompilerOptions` are not
ignored/overwritten. This is also closer to what the cli generates
with the `--enable-ivy` option.
PR Close#29989
George Kalpakas