KVM: selftests: Test vCPU boot IDs above 2^32 and MAX_VCPU_ID

The KVM_SET_BOOT_CPU_ID ioctl missed to reject invalid vCPU IDs. Verify
this no longer works and gets rejected with an appropriate error code.

Signed-off-by: Mathias Krause <minipli@grsecurity.net>
Link: https://lore.kernel.org/r/20240614202859.3597745-6-minipli@grsecurity.net


[sean: add test for MAX_VCPU_ID+1, always do negative test]
Signed-off-by: Sean Christopherson <seanjc@google.com>