Add newly-missing include

Author: adrian-prantl

lldb/unittests/Host/HostInfoTest.cpp

@@ -11,6 +11,7 @@
 #include "TestingSupport/TestUtilities.h"
 #include "lldb/Host/FileSystem.h"
 #include "lldb/lldb-defines.h"
+#include "llvm/Support/Host.h"
 #include "gtest/gtest.h"
 
 using namespace lldb_private;