Added the implementation for vkDeviceWaitIdle, which calls
into a noop vkQueueWaitIdle for now, until we have a non
noop implementation of Fence objects.

This allows many tests to run properly.

Bug b/117835459

Change-Id: I39be52f9462d87591bbb0bccee1e9e41b5a744b9
Reviewed-on: https://swiftshader-review.googlesource.com/c/24048Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>