fix(core): allow dynamic imports during cached module evaluation (#36258)
Fixes #36216
## Summary
Release the `ModuleMapData` borrow before evaluating a cached module in
the synthetic ESM fast path. This allows evaluated module code to start
a dynamic import without re-entering the same `RefCell` while it is
still borrowed.
Add a minimal regression test using a pre-instantiated module cached
under a synthetic ESM specifier whose body starts a dynamic import.
## Root cause
The cache-hit path kept an immutable `ModuleMapData` borrow alive across
`module.evaluate()`. Starting a dynamic import synchronously allocates a
new module load ID, which requires a mutable borrow of the same map and
caused a `RefCell already borrowed` panic.
## Validation
- `./tools/format.js --check`
- `cargo test -p deno_core --lib` (443 passed, 2 ignored)
- `cargo clippy -p deno_core --tests -- -D warnings`