Test handling of IO errors that occur in OsDelete() or OsTruncate() operations. Also use an anonymous file for temporary storage during a VACUUM. (CVS 3729)

FossilOrigin-Name: b24a6e7b024c8b9a0b6fd15bd8f247e458781ca2

src/os_unix.c

@@ -783,6 +783,7 @@ static int transferOwnership(unixFile *pFile){
 ** Delete the named file
 */
 int sqlite3UnixDelete(const char *zFilename){
+  SimulateIOError(return SQLITE_IOERR_DELETE);
   unlink(zFilename);
   return SQLITE_OK;
 }