T24809 segfaults sporadically on windows.
## Summary
T24809 segfaults sporadically on windows.
## Steps to reproduce
```
for ((i=1;;i++)); do echo "Run $i"; hadrian/build -j16 --docs=none --skip-depends --freeze1 test --only=T24809 || break; done
```
## Expected behavior
What do you expect the reproducer described above to do?
## Environment
* GHC version used:
Optional:
* Operating System:
* System Architecture:
issue