Some external device memories really represent existing images
with requirements and not just memory blobs. For AHB, we want
to use the stride from the gralloc buffer.

Bug: b/141698760
Bug: b/147316305
Test: launch_cvd && cts -m CtsDeqpTestCases
  dEQP-VK.api.external.memory.android_hardware_buffer.*
Change-Id: If657c91e458545b58d1d3b0f15f807ca9828b09c
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/50068
Presubmit-Ready: Jason Macnak <natsu@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Tested-by: Jason Macnak <natsu@google.com>