test: stabilize deferred entries HMR assertions (#98418)
### What?
Stabilize the deferred-entries development-mode HMR assertions by giving
condition-based callback, rendered-output, and page-content polling an
HMR-appropriate retry budget.
### Why?
Canary CI repeatedly observed the previous callback timestamp after a
non-deferred edit. The logs show webpack detecting and compiling the
edit, while its multi-compiler HMR cycle—including the edge
compiler—finishes after the generic three-second retry window. The
deferred callback is scheduled after that cycle, so these failures
reflect the harness timing out before valid product behavior rather than
a deferred-entries product defect.
### How?
Use a shared ten-second retry duration only for the six HMR-observable
polls in the existing dev-only tests. The checks still wait on real
callback timestamps, rendered values, and updated page content. Existing
ordering and callback-stability assertions remain unchanged, so missing
callbacks, stale rendering, and callback loops continue to fail.
### Verification
- `pnpm test-dev-webpack
test/e2e/deferred-entries/deferred-entries.test.ts` (3 consecutive runs,
23/23 each, with CI environment mirrored)
- `pnpm test-dev-turbo
test/e2e/deferred-entries/deferred-entries.test.ts` (23/23)
- `pnpm prettier --with-node-modules --ignore-path .prettierignore
--write test/e2e/deferred-entries/deferred-entries.test.ts`
- `npx eslint --config eslint.config.mjs --fix
test/e2e/deferred-entries/deferred-entries.test.ts`
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Co-authored-by: vercel-fleet-prod[bot] <318278635+vercel-fleet-prod[bot]@users.noreply.github.com>
Co-authored-by: Tobias Koppers <1365881+sokra@users.noreply.github.com>
