Cache debugger skip frame predicate (#14386)

I'm not 100% sure this is correct as technically the value of
__debugger_skip__ could change in the current frame while we are
stepping into it, but that is likely super rare, and the slowdown
that this create is problematic.

There is still a small overhead for me, but this should make the
experience much better.

See spyder-ide/spyder-kernels#458,
#13972,
spyder-ide/spyder#20571,
#14382

IPython/core/debugger.py

@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 Pdb debugger class.
 
@@ -101,17 +100,25 @@
 #
 #*****************************************************************************
 
+from __future__ import annotations
+
 import inspect
 import linecache
-import sys
-import re
 import os
+import re
+import sys
+from contextlib import contextmanager
+from functools import lru_cache
 
 from IPython import get_ipython
-from contextlib import contextmanager
-from IPython.utils import PyColorize
-from IPython.utils import coloransi, py3compat
 from IPython.core.excolors import exception_colors
+from IPython.utils import PyColorize, coloransi, py3compat
+
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    # otherwise circular import
+    from IPython.core.interactiveshell import InteractiveShell
 
 # skip module docstests
 __skip_doctest__ = True
@@ -191,6 +198,8 @@ class Pdb(OldPdb):
 
     """
 
+    shell: InteractiveShell
+
     if CHAIN_EXCEPTIONS:
         MAX_CHAINED_EXCEPTION_DEPTH = 999
 
@@ -471,24 +480,11 @@ def precmd(self, line):
 
         return line
 
-    def new_do_frame(self, arg):
-        OldPdb.do_frame(self, arg)
-
     def new_do_quit(self, arg):
-
-        if hasattr(self, 'old_all_completions'):
-            self.shell.Completer.all_completions = self.old_all_completions
-
         return OldPdb.do_quit(self, arg)
 
     do_q = do_quit = decorate_fn_with_doc(new_do_quit, OldPdb.do_quit)
 
-    def new_do_restart(self, arg):
-        """Restart command. In the context of ipython this is exactly the same
-        thing as 'quit'."""
-        self.msg("Restart doesn't make sense here. Using 'quit' instead.")
-        return self.do_quit(arg)
-
     def print_stack_trace(self, context=None):
         Colors = self.color_scheme_table.active_colors
         ColorsNormal = Colors.Normal
@@ -941,11 +937,14 @@ def _is_in_decorator_internal_and_should_skip(self, frame):
         Utility to tell us whether we are in a decorator internal and should stop.
 
         """
-
         # if we are disabled don't skip
         if not self._predicates["debuggerskip"]:
             return False
 
+        return self._cachable_skip(frame)
+
+    @lru_cache
+    def _cachable_skip(self, frame):
         # if frame is tagged, skip by default.
         if DEBUGGERSKIP in frame.f_code.co_varnames:
             return True