syscalls/getitimer: cleanup

1. Remove redundant comments

2. Revise code to follow ltp-code-style

Signed-off-by: DAN LI <li.dan@cn.fujitsu.com>
Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
syscalls/getitimer01.c: Test for getting ITIMER_VIRTUAL and ITIMER_PROF

Additional tests of getting ITIMER_VIRTUAL and ITIMER_PROF.

Signed-off-by: DAN LI <li.dan@cn.fujitsu.com>
Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>