Building DevTools is currently the long pole for the runtime CI job.
Let's see if we can get the overall runtime for runtime build and test
down by speeding this one step up.
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[//]: # (BEGIN SAPLING FOOTER)
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with [ReviewStack](https://reviewstack.dev/facebook/react/pull/32266).
* #32267
* __->__ #32266
Adds tests for Compiler integration.
This includes:
- Tests against Compiler from source.
- Versioned (18.2 - <19) tests against Compiler from npm.
For tests against React 18.2, I had to download `react-compiler-runtime`
from npm and put it to `react/compiler-runtime.js`.