Wait for native window to be ready in VkTest

Some Vulkan tests launch an activity and start a test immediately.
While the test helper assumes that the native window is available,
it may not be created yet or it's being recreated if the display
is rotating.

Let's add a wait to remove this flakiness.

Bug: 233147295
Test: atest android.graphics.cts.VulkanPreTransformTest
Change-Id: I18bcfbd89fb7fe2cb123dd8c980f4afb30fdb7c3
1 file changed