Fast snapshots randomly fail upon restoration in QEMU system mode

**Describe the bug**

When using fast snapshots (syx snapshots) in QEMU system mode to restore OS execution context (GNU/Linux), the snapshot restoration frequently fails and corrupts the OS memory. The issue occurs randomly in most snapshot attempts, making reliable state restoration difficult.

**To Reproduce**

Steps to reproduce the behavior:

1. Set up LibAFL fuzzing with QEMU in system mode
2. Configure fast snapshots
3. Repeatedly create and restore snapshots during fuzzing
4. Observe that in most cases, the restored OS state is corrupted

**Expected behavior**

Fast snapshots should consistently restore the OS execution context without memory corruption. The `restore_fast_snapshot()` function should reliably return the system to a valid state.

**Additional context**

- Through experimentation, I found that calling `check_fast_snapshot()` after `restore_fast_snapshot()` can verify snapshot integrity
- The workaround involves creating a loop that repeatedly takes and restores snapshots until `check_fast_snapshot()` reports no inconsistencies
- Currently, accessing the `nb_page_inconsistencies` field from `QemuSnapshotCheckResult` is not possible as the field is private
- A potential fix would involve making this field accessible (either public or via a getter method) to enable snapshot validation

QEMU launch parameters:

```shell
-cpu max \
-icount auto \
-m 8G \
-L /usr/share/seabios/ \
-L /usr/share/qemu/ \
-L /usr/lib/ipxe/qemu/ \
-uuid aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee \
-drive if=ide,media=disk,id=main_drive,file=./image.qcow2,format=qcow2 \
-netdev user,id=mgmt,net=10.0.2.0/24,restrict=on \
-device e1000,netdev=mgmt,id=mgmt-dev \
-netdev user,id=outside,net=10.0.3.0/24,restrict=on,hostfwd=tcp::8443-:443 \
-device e1000,netdev=outside,id=outside-dev \
-S \
-serial telnet::30007,server=on,wait=off \
-serial mon:telnet::5444,server=on,wait=off \
-nodefaults \
-vga none \
-nographic
```

Device list:

```text
timer, slirp, slirp, cpu_common, cpu, kvm-tpr-opt, apic, 0000:00:00.0/I440FX, PCIHost, PCIBUS, fw_cfg, dma, dma, mc146818rtc, 0000:00:01.1/ide, i2c_bus, 0000:00:01.3/piix4_pm, 0000:00:01.0/PIIX3, i8259, i8259, ioapic, hpet, i8254, pcspk, serial, serial, fdc, ps2kbd, ps2mouse, pckbd, vmmouse, port92, smbus-eeprom, smbus-eeprom, smbus-eeprom, smbus-eeprom, smbus-eeprom, smbus-eeprom, smbus-eeprom, smbus-eeprom, 0000:00:02.0/e1000, 0000:00:03.0/e1000, acpi_build
```