tests: add testing for FS_IOC_FIEMAP

This is limited to FIEMAP.  FICLONE* and FIDEDUPERANGE originated in
btrfs and will be tested there.

* tests/file_ioctl.c: New file.
* tests/file_ioctl.test: New test.
* tests/.gitignore: Add file_ioctl.
* tests/Makefile.am (check_PROGRAMS): Likewise.
(DECODER_TESTS): Add file_ioctl.test.
diff --git a/tests/.gitignore b/tests/.gitignore
index 826aadb..c35f2db 100644
--- a/tests/.gitignore
+++ b/tests/.gitignore
@@ -52,6 +52,7 @@
 fcntl64
 fdatasync
 file_handle
+file_ioctl
 filter-unavailable
 flock
 fork-f