Add explicit triples to AArch64 tests

Only Linux is supported at the moment, and other platforms quickly fault. As a
result these tests would fail on non-Linux hosts. It may be worth making the
tests more generic again as more platforms are supported.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174170 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/DebugInfo/AArch64/variable-loc.ll b/test/DebugInfo/AArch64/variable-loc.ll
index 3277204..194f744 100644
--- a/test/DebugInfo/AArch64/variable-loc.ll
+++ b/test/DebugInfo/AArch64/variable-loc.ll
@@ -1,4 +1,4 @@
-; RUN: llc -march=aarch64 -disable-fp-elim < %s | FileCheck %s
+; RUN: llc -mtriple=aarch64-none-linux-gnu -disable-fp-elim < %s | FileCheck %s
 
 ; This is a regression test making sure the location of variables is correct in
 ; debugging information, even if they're addressed via the frame pointer.