Add a new interceptor for modctl(2) from NetBSD

Summary:
modctl - controls loadable kernel modules.

Skip tests as this call uses privileged operations.

Reviewers: vitalybuka, joerg

Reviewed By: vitalybuka

Subscribers: kubamracek, llvm-commits, mgorny, #sanitizers

Tags: #sanitizers

Differential Revision: https://reviews.llvm.org/D55025

llvm-svn: 348370