Print thread id that belong to arena

[yooo1999]

arena print that struct

struct MallocState {
  int mutex;
  int flags;
  int have_fastchunks;
  pvoid_Array_10 fastbinsY;
  pvoid top;
  pvoid last_remainder;
  pvoid_Array_254 bins;
  int_Array_4 binmap;
  pvoid next;
  pvoid next_free;
  size_t attached_threads;
  size_t system_mem;
  size_t max_system_mem;
}
struct MallocState pwndbg_MallocState;

I offer to print the thread id that belong to that arena ( attached_threads print only the thread count )

[CptGibbon]

Sounds useful 👍
Perhaps printing something like "Arena for thread N:" before the struct is dumped.
I suppose it would only work when no address argument was passed, at least not without doing a lot more legwork to tie an arena to a thread.

[yooo1999]

Arena for thread N: sounds great

[disconnect3d]

Which number do we care about here? I guess the GDB's thread identifier?

Variable: InferiorThread.num
The per-inferior number of the thread, as assigned by GDB.

Variable: InferiorThread.global_num
The global ID of the thread, as assigned by GDB. You can use this to make Python breakpoints thread-specific, for example (see [The Breakpoint.thread attribute](https://sourceware.org/gdb/onlinedocs/gdb/Breakpoints-In-Python.html#python_005fbreakpoint_005fthread)).

Variable: InferiorThread.ptid
ID of the thread, as assigned by the operating system. This attribute is a tuple containing three integers. The first is the Process ID (PID); the second is the Lightweight Process ID (LWPID), and the third is the Thread ID (TID). Either the LWPID or TID may be 0, which indicates that the operating system does not use that identifier.

(via https://sourceware.org/gdb/onlinedocs/gdb/Threads-In-Python.html)

[yooo1999]

@disconnect3d GDB's thread identifier will be great.
Linux's thread identifier will be the best :)

[disconnect3d]

Done in #1583