CP: Reduce max iter count in alloc_callback_fail.device

CP: Reduce max iter count in alloc_callback_fail.device

Creating VkDevice can be costly operation so we need to limit number of
tries to a pretty low value. Other tests already use per-thread limit of
20.

Additionally, this patch adds a way to override the limit by specifying
--deqp-test-iteration-count=N command line parameter. This is useful for
full OOM testing.

Bug: 30811856

(cherry picked from commit 3b17fd4c4e2d450f34f68989ff786939032cdcb9)

Change-Id: Ib3aaeff24d7753d52a6a444abfbecf863803c9ec