[NewPM] Add explicit triple to test

This prevents warnings like:

> warning: overriding the module target triple with x86_64-apple-darwin

on macOS.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@354008 91177308-0d34-0410-b5e6-96231b3b80d8

test/CodeGen/asan-new-pm.ll

@@ -6,6 +6,8 @@
 ; RUN: %clang_cc1 -S -emit-llvm -o - -O1 -fexperimental-new-pass-manager -fsanitize=address -flto %s | FileCheck %s --check-prefixes=CHECK,LTO
 ; RUN: %clang_cc1 -S -emit-llvm -o - -O1 -fexperimental-new-pass-manager -fsanitize=address -flto=thin %s | FileCheck %s --check-prefixes=CHECK,THINLTO
 
+target triple = "x86_64-unknown-unknown"
+
 ; DAG-CHECK: @llvm.global_ctors = {{.*}}@asan.module_ctor
 
 define i32 @test_load(i32* %a) sanitize_address {