Disable S3 tests due to recent failures

It looks like SSL Verify = NO doesn't work for 10.5
https://buildbot.mariadb.org/#/builders/369/builds/26765/steps/13/logs/stdio

Will disable S3 tests until we figure it out.

constants.py

@@ -61,10 +61,7 @@
     "ppc64le-ubuntu-2204",
     "amd64-freebsd-14",
 ]
-builders_s3_mtr = [
-    "amd64-ubuntu-2004-debug",
-    "s390x-sles-1506",
-]
+builders_s3_mtr = []
 
 # Defines branches for which we save packages
 savedPackageBranches = branches_main + [