fix: race condition in CLI output in react-compiler test (#65909)
the 'should show an experimental warning' test in
`react-compiler-test.ts` has been randomly flaking for me:
```
Expected substring: "Experiments (use with caution)"
Received string: " ⚠ `experimental.ppr` has been defaulted to `true` because `__NEXT_EXPERIMENTAL_PPR` was set to `true` during testing.
⚠ `experimental.ppr` has been defaulted to `true` because `__NEXT_EXPERIMENTAL_PPR` was set to `true` during testing.
▲ Next.js 14.3.0-canary.69
- Local: http://localhost:40095
"
```
when the actual CLI output is:
```
⚠ `experimental.ppr` has been defaulted to `true` because `__NEXT_EXPERIMENTAL_PPR` was set to `true` during testing.
⚠ `experimental.ppr` has been defaulted to `true` because `__NEXT_EXPERIMENTAL_PPR` was set to `true` during testing.
▲ Next.js 14.3.0-canary.69
- Local: http://localhost:40095
- Experiments (use with caution):
· reactCompiler
```
which indicates that we're reading the CLI output too early
next.js
8747e235 - fix: race condition in CLI output in react-compiler test (#65909)
