fix(profiler): decrement refcount given strong reference of frame object in python 3.11 [backport] (#4951)

## Description
Backports for #4901 and #4937 to 1.7.

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Co-authored-by: Brett Langdon <[email protected]>

Author: Yun-Kim

ddtrace/profiling/collector/stack.pyx

@@ -257,6 +257,7 @@ cdef collect_threads(thread_id_ignore_list, thread_time, thread_span_links) with
                                 if exc_tb:
                                     current_exceptions[tstate.thread_id] = (<object>exc_type, <object>exc_tb)
                                 Py_XDECREF(exc_tb)
+                            Py_XDECREF(frame)
                         ELSE:
                             frame = tstate.frame
                             if frame:

releasenotes/notes/fix-profiler-3-11-memory-leak-stack-collector-9131642011ee5ce8.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    profiling: This fix resolves an issue in Python 3.11 where a PyFrameObject strong reference count was not properly
+    decremented in the stack collector.

tests/profiling/collector/test_stack.py

@@ -1,10 +1,12 @@
 # -*- encoding: utf-8 -*-
 import collections
+import gc
 import os
 import sys
 import threading
 import time
 import timeit
+from types import FrameType
 import typing
 import uuid
 
@@ -400,7 +402,7 @@ def test_exception_collection():
     assert e.sampling_period > 0
     assert e.thread_id == nogevent.thread_get_ident()
     assert e.thread_name == "MainThread"
-    assert e.frames == [(__file__, 394, "test_exception_collection", "")]
+    assert e.frames == [(__file__, 396, "test_exception_collection", "")]
     assert e.nframes == 1
     assert e.exc_type == ValueError
 
@@ -432,7 +434,7 @@ def test_exception_collection_trace(
     assert e.sampling_period > 0
     assert e.thread_id == nogevent.thread_get_ident()
     assert e.thread_name == "MainThread"
-    assert e.frames == [(__file__, 421, "test_exception_collection_trace", "")]
+    assert e.frames == [(__file__, 423, "test_exception_collection_trace", "")]
     assert e.nframes == 1
     assert e.exc_type == ValueError
     assert e.span_id == span.span_id
@@ -743,3 +745,20 @@ def _nothing():
     # assert (exact_time * 0.7) <= values.pop() <= (exact_time * 1.3)
 
     assert values.pop() > 0
+
+
+@pytest.mark.skipif(sys.version_info < (3, 11, 0), reason="PyFrameObjects are lazy-created objects in Python 3.11+")
+def test_collect_ensure_all_frames_gc():
+    # Regression test for memory leak with lazy PyFrameObjects in Python 3.11+
+    def _foo():
+        pass
+
+    r = recorder.Recorder()
+    s = stack.StackCollector(r)
+
+    with s:
+        for _ in range(100):
+            _foo()
+
+    gc.collect()  # Make sure we don't race with gc when we check frame objects
+    assert sum(isinstance(_, FrameType) for _ in gc.get_objects()) == 0