fix(test): use alternative URL for Spectre/Meltdown checker

The link we were using to download the Spectre/Meltdown checker script
stopped working and caused our CI to fail consistently.

Use this alternative link to download the script.

(cherry picked from commit e5b4f26)

Signed-off-by: Babis Chalios <[email protected]>

Author: bchalios

tests/integration_tests/security/test_vulnerabilities.py

@@ -17,7 +17,7 @@
 from framework.microvm import MicroVMFactory
 from framework.properties import global_props
 
-CHECKER_URL = "https://meltdown.ovh"
+CHECKER_URL = "https://raw.githubusercontent.com/speed47/spectre-meltdown-checker/master/spectre-meltdown-checker.sh"
 CHECKER_FILENAME = "spectre-meltdown-checker.sh"
 REMOTE_CHECKER_PATH = f"/tmp/{CHECKER_FILENAME}"
 REMOTE_CHECKER_COMMAND = f"sh {REMOTE_CHECKER_PATH} --no-intel-db --batch json"