Snapshot issues in next-dev-tests (#3774)
This:
* Adds issue snapshot support to next-dev-tests. This will allow us to
assert that certain issues are raised in tests that require next-dev.
* Extracts common snapshot code into a new crates,
`turbopack-test-utils`, which is shared between snapshot tests and
next-dev-tests.
* Implements an issue reporter that emits issues in a channel to the the
integration test code, where they are snapshotted.
* Fixes an issue where next-dev tests that were not Next.js apps would
emit non-fatal issues for a missing `pages/` directory.
Co-authored-by: Justin Ridgewell <justin@ridgewell.name>
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Co-authored-by: Justin Ridgewell <justin@ridgewell.name>
