Handle sync_fd==-1

According to spec:

https://registry.khronos.org/vulkan/specs/1.3-extensions/man/html/VkImportSemaphoreFdInfoKHR.html

If handleType is VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BIT,
the special value -1 for fd is treated like a valid sync file
descriptor referring to an object that has already signaled. The
import operation will succeed and the VkSemaphore will have a
temporarily imported payload as if a valid file descriptor had been
provided.

Bug: 245411781
Test: dEQP-VK.api.external.semaphore.sync_fd#import_signaled_temporary
Change-Id: I29675fac717432d76a09857b69786c8368c968f8