block: Add raw_async_io_tests shared test helpers

Add raw_async_io_tests.rs with punch_hole, write_zeroes, and
multiple_operations helpers that take &mut dyn AsyncIo + &mut File.
These are raw-backend-specific. They verify data by reading the
underlying file directly, which only works for plain file backends
without container format metadata.

Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>

block/src/lib.rs

@@ -24,6 +24,8 @@ pub mod qcow_sync;
 /// Enabled with the `"io_uring"` feature
 pub mod raw_async;
 pub mod raw_async_aio;
+#[cfg(test)]
+mod raw_async_io_tests;
 pub mod raw_sync;
 pub mod vhd;
 pub mod vhdx;