add a D script to report VMs' CPUID queries

[iximeow]

a better version of the script from #933, actually worth holding on to.

here's a Debian 11 image booting:

# dtrace -s cpuid-queries.d 0xffffff35739b7000
<skipping some awfully noisy grub stuff>
CPUID query: leaf/subleaf 0x80000000/0x00000000, returns rax = 0x80000028, rbx = 0x68747541, rcx = 0x444d4163, rdx = 0x69746e65
CPUID query: leaf/subleaf 0x80000008/0x00000000, returns rax = 0x00003030, rbx = 0x00000007, rcx = 0x00000000, rdx = 0x00010000
CPUID query: leaf/subleaf 0x00000000/0x00000000, returns rax = 0x00000010, rbx = 0x68747541, rcx = 0x444d4163, rdx = 0x69746e65
CPUID query: leaf/subleaf 0x00000001/0x00000000, returns rax = 0x00a60f12, rbx = 0x00020800, rcx = 0xf6d83203, rdx = 0x178bfbff
CPUID query: leaf/subleaf 0x00000001/0x00000000, returns rax = 0x00a60f12, rbx = 0x00020800, rcx = 0xf6d83203, rdx = 0x178bfbff
CPUID query: leaf/subleaf 0x00000006/0x00000000, returns rax = 0x00000004, rbx = 0x00000000, rcx = 0x00000000, rdx = 0x00000000
CPUID query: leaf/subleaf 0x00000007/0x00000000, returns rax = 0x00000000, rbx = 0xf01703a9, rcx = 0x00000600, rdx = 0x00000000
CPUID query: leaf/subleaf 0x0000000d/0x00000001, returns rax = 0x00000001, rbx = 0x00000240, rcx = 0x00000000, rdx = 0x00000000
CPUID query: leaf/subleaf 0x80000000/0x00000000, returns rax = 0x80000028, rbx = 0x68747541, rcx = 0x444d4163, rdx = 0x69746e65
CPUID query: leaf/subleaf 0x80000001/0x00000000, returns rax = 0x00a60f12, rbx = 0x00000000, rcx = 0x444031fb, rdx = 0x25d3fbff
CPUID query: leaf/subleaf 0x80000007/0x00000000, returns rax = 0x00000000, rbx = 0x00000000, rcx = 0x00000000, rdx = 0x00000100
CPUID query: leaf/subleaf 0x80000008/0x00000000, returns rax = 0x00003030, rbx = 0x00000007, rcx = 0x00000000, rdx = 0x00010000
CPUID query: leaf/subleaf 0x8000000a/0x00000000, returns rax = 0x00000001, rbx = 0x00008000, rcx = 0x00000000, rdx = 0x1ebfbcff
CPUID query: leaf/subleaf 0x8000001f/0x00000000, returns rax = 0x00000001, rbx = 0x000000b3, rcx = 0x00000000, rdx = 0x00000000
CPUID query: leaf/subleaf 0x80000021/0x00000000, returns rax = 0x00062fcf, rbx = 0x0000015c, rcx = 0x00000000, rdx = 0x00000000
CPUID query: leaf/subleaf 0x00000000/0x00000000, returns rax = 0x00000010, rbx = 0x68747541, rcx = 0x444d4163, rdx = 0x69746e65
CPUID query: leaf/subleaf 0x00000006/0x00000000, returns rax = 0x00000004, rbx = 0x00000000, rcx = 0x00000000, rdx = 0x00000000
CPUID query: leaf/subleaf 0x00000000/0x00000000, returns rax = 0x00000010, rbx = 0x68747541, rcx = 0x444d4163, rdx = 0x69746e65
CPUID query: leaf/subleaf 0x00000006/0x00000000, returns rax = 0x00000004, rbx = 0x00000000, rcx = 0x00000000, rdx = 0x00000000

it'd be nice to elide the subleaf for leaves that do not have subleaves, output like

CPUID query: leaf/subleaf 0x00000000/0x7fac95621e97, returns rax = 0x00000010, rbx = 0x68747541, rcx = 0x444d4163, rdx = 0x69746e65
CPUID query: leaf/subleaf 0x00000001/0x7ffd11ee380c, returns rax = 0x00a60f12, rbx = 0x00020800, rcx = 0xfed83203, rdx = 0x178bfbff

is not ideal.. need to have a better treatment of CPUID leaves elsewhere so i might maybe generate a list of known leaf-y/subleaf-y leaves for this. but also if you're looking at this i assume you'll figure out pretty quick which "subleaf" items are not actually relevant.