Fine. Write URIs and lookup names as string refs in manifests

Switch serialization of heavily repeated strings (URIs, `LookupName`s,
and select identifiers) from inline UTF-8 blobs to string references
backed by a per-blob string table. Readers now initialize the table from
the end of the buffer, and writers emit it once at the end.

This cuts duplication in library/requirements/diagnostics bundles and
improves both size and speed when analyzing the analyzer:
- size: 112 MB → 62 MB (~45% smaller)
- time: 450 ms → 310 ms (~31% faster)

Key changes
- Use `writeStringReference` / `readStringReference` for:
  - URIs (`writeUri`/`readUri`); parse via `uriCache.parse`.
  - `LookupName`, `BaseName`, and various manifest/type strings
    (e.g., token buffers, member/top-level names, record field names,
    named parameter names).
- Add `writeStringTableAtEnd()` in all writers that produce persisted
  blobs, and `initializeStringTableFromEnd()` in matching readers:
  - `LinkedBundleProvider` (get/put paths)
  - `LibraryDiagnosticsBundle` (toBytes/fromBytes)
  - Manifest and requirements assert-serialization paths
- Bump `AnalysisDriver.DATA_VERSION` to 561 to invalidate old caches.

Why this works
- Manifests and requirements repeat the same URIs and names across many
  entries. Interning them through a string table removes redundancy and
  reduces I/O.
- `uriCache.parse` avoids repeated `Uri` allocations and speeds up
  lookup.

Trade-offs
- Writers must call `writeStringTableAtEnd()` exactly once after all
  payload writes and before `takeBytes()`.
- Readers that consume string references must initialize the table
  before any reference reads.

Change-Id: I2346e02fa34e0f421b6f15ccd485a0d19b00062d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/451126
Reviewed-by: Paul Berry <paulberry@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>