[analyzer] Hotfix for buildbot failure due to unspecified triple in r277449

If a target triple is not specified, the default host triple is used,
which is not good for compiling inline assembler code.

Patch by Raphael Isemann!


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@277473 91177308-0d34-0410-b5e6-96231b3b80d8