[Sema] Remove unneeded TreeTransform.h includes, NFC

SemaDecl.cpp and SemaType.cpp don't have any TreeTransforms.

Author: rnk

clang/lib/Sema/SemaDecl.cpp

@@ -10,7 +10,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "TreeTransform.h"
 #include "TypeLocBuilder.h"
 #include "clang/AST/ASTConsumer.h"
 #include "clang/AST/ASTContext.h"

clang/lib/Sema/SemaType.cpp

@@ -11,7 +11,6 @@
 //===----------------------------------------------------------------------===//
 
 #include "TypeLocBuilder.h"
-#include "TreeTransform.h"
 #include "clang/AST/ASTConsumer.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/ASTMutationListener.h"