treewide: remove qemu build

We aren't bundling it right now and it is fairly out of date. Let's kick
it out until we need it, then reengineer the build.

Change-Id: I5362616922d4b9d3e971868636f3792e33880f7a
Reviewed-on: https://review.monogon.dev/c/monogon/+/3568
Reviewed-by: Lorenz Brun <lorenz@monogon.tech>
Tested-by: Jenkins CI
diff --git a/third_party/sandboxroot/regenerate.sh b/third_party/sandboxroot/regenerate.sh
index bb0b679..8f02692 100755
--- a/third_party/sandboxroot/regenerate.sh
+++ b/third_party/sandboxroot/regenerate.sh
@@ -46,6 +46,7 @@
 
   # ktest
   "qemu-system-x86-core"
+  "qemu-img"
 
   # musl-host-gcc
   "rsync"