tests/qtest/migration-test: Run some basic tests on s390x and ppc64 with TCG, too

tests/qtest/migration-test: Run some basic tests on s390x and ppc64 with TCG, too

On s390x, we recently had a regression that broke migration / savevm
(see commit bebe9603fc ("hw/intc/s390_flic: Fix crash that occurs when
saving the machine state"). The problem was merged without being noticed
since we currently do not run any migration / savevm related tests on
x86 hosts.
While we currently cannot run all migration tests for the s390x target
on x86 hosts yet (due to some unresolved issues with TCG), we can at
least run some of the non-live tests to avoid such problems in the future.
Thus enable the "analyze-script" and the "bad_dest" tests before checking
for KVM on s390x or ppc64 (this also fixes the problem that the
"analyze-script" test was not run on s390x at all anymore since it got
disabled again by accident in a previous refactoring of the code).

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>