Add new interceptor for mi_vector_hash(3)

Summary:
mi_vector_hash(3) provides fast 32bit hash functions.

Add a test for this interface.

Enable the API for NetBSD.

Based on original work by Yang Zheng.

Reviewers: joerg, vitalybuka

Reviewed By: vitalybuka

Subscribers: tomsun.0.7, kubamracek, llvm-commits, mgorny, #sanitizers

Tags: #sanitizers

Differential Revision: https://reviews.llvm.org/D54530

llvm-svn: 347088