Previously, calling `Process#kill()` after the process had exited would
sometimes throw a `TypeError` on Windows. After this patch, it will
throw `NotFound` instead, just like other platforms.
This patch also fixes flakiness of the `runKillAfterStatus` test on
Windows.
This commit renames two assertion functions to better align with JS API:
- assertStringContains -> assertStringIncludes
- assertArrayContains -> assertArrayIncludes
This commit fixes panic caused by "unimplemented!()"
calls for some variants of "nix::errno::Errno".
Catch-all variant now returns "Error" class name
instead of panicking.
Co-authored-by: Bert Belder <bertbelder@gmail.com>