DF-4926 baseline decisive run (stock nvmm.ko) — serial console (dfbsd-qemu/boot.log), guest DOWN:

  login: nvmm: attached, using backend x86-vmx
  FaStopped at      nvmm_ioctl+0x444:       movq    0x48(%rax),%rax
  db>

(two baseline runs, identical crash site; run 2 crashed on the FIRST kldunload;
 full excerpt in panic.txt; the trap banner is truncated on the crashing console)

== racer calibration (standalone, stock module, testnv uid 1002) ==
DF-4926 racer: fd=3 mode=combined (uid=1002)
t= 1s cap=1098282 create=19895 destroy=19895
t= 2s cap=1892941 create=39935 destroy=39935