If running multiple VBox VMMs with Windows as guest concurrently then it may
happen that the system seem to hang. It turned out that actually
a VM-exit storm (vmx_exception->handle_exc_nm) causes a endless loop between
kernel and vCPU. Nothing gets scheduled nor interrupts are received anymore.
The referenced kernel commit fixes this issue.
Issue #1343
The commit uses a fixed kernel branch (r8), which fixes a caching bug
observable in the Genode host. The quirk detecting the circumstance in the
timer service is obsolete now and is removed.
Fixes#1338
