All changes in this commit were generated by the following commands.
Copy each module that ends with `.old` to a new file that ends
with `.new`:
```sh
for f in packages/react-reconciler/src/*.old.js; do cp "$f" "$(echo "$f" | sed s/\.old/\.new/)"; done
```
Then transform the internal imports:
```sh
grep -rl --include="*.new.js" '.old' packages/react-reconciler/src/| xargs sed -i '' "s/\.old\'/\.new\'/g"
```
Andrew Clark