gdb: remove unused includes in objfiles.{c,h}

Remove some includes reported as unused by clangd.

Change-Id: I7768232c28b9b86b0a03628a1d15dede2b30c76a

gdb/objfiles.c

@@ -27,7 +27,6 @@
 #include "symfile.h"
 #include "objfiles.h"
 #include "target.h"
-#include "bcache.h"
 #include "expression.h"
 #include "parser-defs.h"
 
@@ -46,13 +45,11 @@
 #include "exec.h"
 #include "observable.h"
 #include "complaints.h"
-#include "solist.h"
 #include "gdb_bfd.h"
 #include "btrace.h"
 #include "gdbsupport/pathstuff.h"
 
 #include <algorithm>
-#include <vector>
 
 /* Externally visible variables that are owned by this module.
    See declarations in objfile.h for more info.  */

gdb/objfiles.h

@@ -20,21 +20,15 @@
 #if !defined (OBJFILES_H)
 #define OBJFILES_H
 
-#include "hashtab.h"
 #include "gdbsupport/gdb_obstack.h"
 #include "objfile-flags.h"
 #include "symfile.h"
 #include "progspace.h"
 #include "registry.h"
 #include "gdb_bfd.h"
-#include <atomic>
 #include <bitset>
-#include <vector>
-#include "gdbsupport/next-iterator.h"
-#include "gdbsupport/safe-iterator.h"
 #include "bcache.h"
 #include "gdbarch.h"
-#include "gdbsupport/refcounted-object.h"
 #include "jit.h"
 #include "quick-symbol.h"
 #include <forward_list>