Purge unused includes throughout libSupport.

NFC.

llvm-svn: 232976
diff --git a/llvm/tools/lli/lli.cpp b/llvm/tools/lli/lli.cpp
index 9c2b781..cc8117d 100644
--- a/llvm/tools/lli/lli.cpp
+++ b/llvm/tools/lli/lli.cpp
@@ -42,6 +42,7 @@
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/Memory.h"
 #include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Path.h"
 #include "llvm/Support/PluginLoader.h"
 #include "llvm/Support/PrettyStackTrace.h"
 #include "llvm/Support/Process.h"