c8 is cashing filename/directories which do not update on change

* **Version**: v19.8.1
* **Platform**: Darwin 22.1.0 Darwin Kernel Version 22.1.0 arm64

I ran c8 once, then changed the file-naming and folder structure, and ran c8 again. The paths do not update as expected in the coverage. I've deleted the coverage folder and pretty much all generated files - still no luck.

If I change the naming of certain exports, then the file paths update to their correct paths. However, if I revert them back to their original export values, the old paths are used again.

```
---------------|---------|----------|---------|---------|-------------------
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
---------------|---------|----------|---------|---------|-------------------
All files | 100 | 100 | 100 | 100 |
nodes | 100 | 100 | 100 | 100 |
token.ts | 100 | 100 | 100 | 100 |
printer/nodes | 100 | 100 | 100 | 100 |
base-node.ts | 100 | 100 | 100 | 100 |
printer/utils | 100 | 100 | 100 | 100 |
index.ts | 100 | 100 | 100 | 100 |
```

The `printer/` folder no longer exists, and `printer/nodes/` was moved to `nodes/`. As seen in the above output, new coverage tests reflect the latest path eg `nodes/token.ts`, but old coverage tests still use the old paths eg `printer/nodes/base-nodes.ts`.