perf(rcstr): Support inline string (#74482)
### What?
Support inline string for `RcStr`. Most of the code is copied from
https://github.com/dudykr/ddbase/tree/67c7cec871073f5c8c93d030d40fb8226170797f/crates/hstr/src
(I own the code)
### Why?
To see at the perf difference.
#### Command: `ddt profile instruments run -t Memory -- $(which node)
$(which pnpm) build-turbopack`
- Old:
<img width="1840" alt="image"
src="https://github.com/user-attachments/assets/e9946dcf-7509-42ed-8648-6f6589de6313"
/>
- New:
<img width="1840" alt="image"
src="https://github.com/user-attachments/assets/08ea782e-9c66-4537-94a3-9f63956aa11a"
/>
### How?
