Adapt UBSan integer truncation tests to NetBSD

Summary:
The NetBSD headers use internal indirect type for
standard *int*_t  definitions. The internal type is unrolled
inside the sanitizer into e.g. __int32_t from int32_t.

This symbol mangling causes pattern mismatch in
the interger truncation tests as they expect exact
types such as 'int32_t'.

Change the pattern rules so every acceptable internal
form of *int*_t will be accepted flawlessly.

Reviewers: lebedev.ri, vitalybuka, joerg

Reviewed By: lebedev.ri

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

Tags: #sanitizers

Differential Revision: https://reviews.llvm.org/D54150

llvm-svn: 346228