tests/prom-env-test: increase the test timeout

On a slower machine the test can take more than 30 seconds.
Increase the timeout to 100 seconds.
Signed-off-by: NMarcel Apfelbaum <marcel@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Tested-by: NMark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

tests/prom-env-test.c

@@ -30,7 +30,7 @@ static void check_guest_memory(void)
     int i;
 
     /* Poll until code has run and modified memory. Wait at most 30 seconds */
-    for (i = 0; i < 3000; ++i) {
+    for (i = 0; i < 10000; ++i) {
         signature = readl(ADDRESS);
         if (signature == MAGIC) {
             break;