[gdb] Limit stack search when looking for DCHECK

Only look 5 frames up the stack when looking for a DCHECK to move the
frame to to prevent excessive iteration especially after a stack
overflow.

Change-Id: I227c46596f09c9af0a47e6673d3165eaccb75163
Reviewed-on: https://chromium-review.googlesource.com/c/1400408
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58621}

tools/gdbinit

@@ -140,7 +140,11 @@ def dcheck_stop_handler(event):
   frame = gdb.selected_frame()
   select_frame = None
   message = None
-  while frame is not None:
+  count = 0
+  # limit stack scanning since they're usually shallow and otherwise stack
+  # overflows can be very slow.
+  while frame is not None and count < 5:
+    count += 1
     if frame.name() == 'V8_Dcheck':
       frame_message = gdb.lookup_symbol('message', frame.block())[0]
       if frame_message: