tests/avocado/migration: Remove the malfunctioning s390x tests

The tests from tests/avocado/migration.py do not work at all
on s390x - the bios shuts down immediately when it cannot find
a boot disk, so there is nothing left to migrate here. For doing
a proper migration test, we would need a proper payload, but we
already do such tests in the migration *qtest*, so it is unnecessary
to redo such a test here, thus let's simply remove this test.

Message-Id: <20230721164346.10112-1-thuth@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

tests/avocado/migration.py

@@ -134,21 +134,3 @@ def test_migration_with_unix(self):
 
     def test_migration_with_exec(self):
         self.migration_with_exec()
-
-
-@skipUnless('s390x' in os.uname()[4], "host != target")
-class S390X(MigrationTest):
-    """
-    :avocado: tags=arch:s390x
-    :avocado: tags=machine:s390-ccw-virtio
-    :avocado: tags=cpu:qemu
-    """
-
-    def test_migration_with_tcp_localhost(self):
-        self.migration_with_tcp_localhost()
-
-    def test_migration_with_unix(self):
-        self.migration_with_unix()
-
-    def test_migration_with_exec(self):
-        self.migration_with_exec()