tests/machine-none: Make test independent of global_qtest

Apart from using qmp() in one spot, this test does not have any
dependencies to the global_qtest variable, so we can simply get
rid of it here by replacing the qmp() with qtest_qmp().
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NThomas Huth <thuth@redhat.com>

tests/machine-none-test.c

@@ -75,6 +75,7 @@ static void test_machine_cpu_cli(void)
     QDict *response;
     const char *arch = qtest_get_arch();
     const char *cpu_model = get_cpu_model_by_arch(arch);
+    QTestState *qts;
 
     if (!cpu_model) {
         if (!(!strcmp(arch, "microblaze") || !strcmp(arch, "microblazeel"))) {
@@ -83,13 +84,13 @@ static void test_machine_cpu_cli(void)
         }
         return; /* TODO: die here to force all targets have a test */
     }
-    global_qtest = qtest_initf("-machine none -cpu '%s'", cpu_model);
+    qts = qtest_initf("-machine none -cpu '%s'", cpu_model);
 
-    response = qmp("{ 'execute': 'quit' }");
+    response = qtest_qmp(qts, "{ 'execute': 'quit' }");
     g_assert(qdict_haskey(response, "return"));
     qobject_unref(response);
 
-    qtest_quit(global_qtest);
+    qtest_quit(qts);
 }
 
 int main(int argc, char **argv)