Fix cleanup of swapchain images in the shared case

Previously we'd fail to call DestroyImage for images in the shared
swapchain. We only need to skip cancelBuffer.

Bug: b/78779994
Test: dEQP-VK.wsi.android.*
Change-Id: Ic95887fb76a8ab5d01e6e3aaa3f63dddc697ea4c
1 file changed