Fix test case introduced in r214322

This patch adds an explicit triple to the test case introduced by r214322. This
should fix build failueres that are occuring on bots that are cross building.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214330 91177308-0d34-0410-b5e6-96231b3b80d8