[Lex] Remove unused includes (NFC) (llvm#141523)

These are identified by misc-include-cleaner.  I've filtered out those
that break builds.  Also, I'm staying away from llvm-config.h,
config.h, and Compiler.h, which likely cause platform- or
compiler-specific build failures.

Author: kazutakahirata

clang/lib/Lex/HeaderMap.cpp

@@ -18,7 +18,6 @@
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/MemoryBuffer.h"
-#include "llvm/Support/SystemZ/zOSSupport.h"
 #include <cstring>
 #include <memory>
 #include <optional>

clang/lib/Lex/ModuleMap.cpp

@@ -37,9 +37,7 @@
 #include "llvm/Support/Path.h"
 #include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Support/raw_ostream.h"
-#include <algorithm>
 #include <cassert>
-#include <cstdint>
 #include <cstring>
 #include <optional>
 #include <string>

clang/lib/Lex/ModuleMapFile.cpp

@@ -20,8 +20,6 @@
 #include "clang/Lex/Lexer.h"
 #include "clang/Lex/ModuleMap.h"
 #include "llvm/ADT/STLExtras.h"
-#include "llvm/Support/Error.h"
-#include "llvm/Support/Format.h"
 #include <optional>
 
 using namespace clang;