[NFC] Header cleanup

Removed some unused headers, replaced some headers with forward class declarations.

Found using simple scripts like this one:
clear && ack --cpp -l '#include "llvm/ADT/IndexedMap.h"' | xargs grep -L 'IndexedMap[<]' | xargs grep -n --color=auto 'IndexedMap'

Patch by Eugene Kosov <claprix@yandex.ru>

Differential Revision: http://reviews.llvm.org/D19219

From: Mehdi Amini <mehdi.amini@apple.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266595 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 0 insertions, 2 deletions

diff --git a/lib/TableGen/TGParser.cpp b/lib/TableGen/TGParser.cpp
index d3b6c50edff..4239628498b 100644
--- a/lib/TableGen/TGParser.cpp
+++ b/lib/TableGen/TGParser.cpp
@@ -15,10 +15,8 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringExtras.h"
-#include "llvm/Support/CommandLine.h"
 #include "llvm/TableGen/Record.h"
 #include <algorithm>
-#include <sstream>
 using namespace llvm;
 
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