VkBuffers backed by AHBs do not require dedicated allocations.
As such, update SupportsAllocateInfo() to report supported as
long as a VkImportAndroidHardwareBufferInfoANDROID or a
VkExportMemoryAllocateInfo with AHB bit was found.

Updates allocateAndroidHardwareBuffer() to treat the lack of a
dedicated buffer or image as a request to allocate a blob AHB.

Bug: b/147316305
Bug: b/169796031
Test: cts -m CtsNativeHardwareTestCases
Test: cts -m CtsDeqpTestCases -t
  dEQP-VK.api.external.memory.android_hardware_buffer.*
Change-Id: Ica2782b4570bd4d4c1e5585b696b40314a267b2f
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/51248
Presubmit-Ready: Jason Macnak <natsu@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Tested-by: Jason Macnak <natsu@google.com>
Commit-Queue: Jason Macnak <natsu@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>