Increase sync_file_range() coverage

[metan-ucw]

At the moment the sync_file_range01 test covers only negative testcases, i.e. invalid inputs passed to the syscall. We need a functionality test as well.

[acerv]

sync_file_range02 has been implemented already and ticket can be closed

[pevik]

Yeah, thanks! https://github.com/linux-test-project/ltp/tree/master/testcases/kernel/syscalls/sync_file_range/sync_file_range02.c