Some of these tests were marked as UNIMPLEMENTED because of an
unhandled extension structure.

Bug b/132185385

Change-Id: Ie1f399d1d69490976950b268dc96225e4c57b174
Tests: dEQP-VK.memory.external_memory_host.*
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/30809
Presubmit-Ready: Alexis Hétu <sugoi@google.com>
Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>