anv: Add explicit-sync for Android
Replace implicit-sync code from AcquireImageANDROID / QueueSignalReleaseImageANDROID with an explicit-sync version.
Additionally, fix a possible crash when ImportSemaphoreFdKHR receives -1 as Fd. When that is the case, it creates an already signaled syncobj.
This was tested in ChromeOS ARC. And it based on the Work-In-Progress patch from here: https://chromium-review.googlesource.com/c/chromiumos/overlays/chromiumos-overlay/+/2243414