This skips test that use a lot of memory. In particular, there's
one test that would use up to 6.8 GB of memory, while the GitHub
Actions runners only have 8 GB of memory available.
This parameter was added in 122064a6303eb9c06e0af231f5a4ce145d9a2e67
in the llvm-project main branch, and backported to 17.x in
aa03fba83b17bbfcd9ed869efed2818b503875d6.
Ninja isn't documented as one of the tools provided by the CI runner
images, but it used to be available implicitly installed before
in the windows-2022 images. Since the 20230918.1.0 image update,
it no longer is available out of the box; see
https://github.com/actions/runner-images/issues/8343.