queueFamilyIndices are only valid in VK_SHARING_MODE_CONCURRENT mode,
so Buffers were copying garbage in VK_SHARING_MODE_EXCLUSIVE mode.
This cl allows dEQP-VK.robustness.* tests to run and fail rather than
immediately crash at Buffer construction time.

Bug b/118383648
Tests: dEQP-VK.robustness.*

Change-Id: I5b82348317e12302359e082088ed5d10f6367e0e
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/28311
Presubmit-Ready: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Alexis Hétu <sugoi@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>