Write test for/investigate lookup_dcookie()

[rafaeldtinoco]

Likely missing coverage for lookup_dcookie() syscall.

See: http://man7.org/linux/man-pages/man2/lookup_dcookie.2.html

OBS: Part of Linaro effort for full arm32/arm64 syscall coverage. OBS: Low priority, seems to be o-profile related only.

[acerv]

I'm not sure if it makes sense to test this feature anymore, since it's used by a single software (oprofile) that is many years old already.