[TableGen] Remove unnecessary includes (NFC)

Identified with clangd.

Author: kazutakahirata

llvm/lib/TableGen/JSONBackend.cpp

@@ -11,7 +11,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"

llvm/unittests/TableGen/AutomataTest.cpp

@@ -6,7 +6,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/Automaton.h"

llvm/utils/TableGen/GlobalISelMatchTableExecutorEmitter.h

@@ -20,7 +20,6 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
 #include <functional>
-#include <vector>
 
 namespace llvm {
 class CodeGenTarget;

llvm/utils/TableGen/IntrinsicEmitter.cpp

@@ -12,7 +12,6 @@
 
 #include "CodeGenIntrinsics.h"
 #include "SequenceToOffsetTable.h"
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringExtras.h"