Move endian constant from Host.h to SwapByteOrder.h, prune include

Works on this dependency chain:
  ArrayRef.h ->
  Hashing.h -> --CUT--
  Host.h ->
  StringMap.h / StringRef.h

ArrayRef is very popular, but Host.h is rarely needed. Move the
IsBigEndianHost constant to SwapByteOrder.h. Clients of that header are
more likely to need it.

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@375316 91177308-0d34-0410-b5e6-96231b3b80d8

clangd/FileDistance.h

diff --git a/clangd/FileDistance.h b/clangd/FileDistance.h
index e7174bc..88bb30c 100644
--- a/clangd/FileDistance.h
+++ b/clangd/FileDistance.h
@@ -43,6 +43,7 @@
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/DenseMapInfo.h"
 #include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/Path.h"