[3.14] gh-137400: Fix thread-safety issues when profiling all threads (gh-137518) (gh-137730)

There were a few thread-safety issues when profiling or tracing all
threads via PyEval_SetProfileAllThreads or PyEval_SetTraceAllThreads:

* The loop over thread states could crash if a thread exits concurrently
  (in both the free threading and default build)
* The modification of `c_profilefunc` and `c_tracefunc` wasn't
  thread-safe on the free threading build.
(cherry picked from commit a10152f8fd)

Co-authored-by: Sam Gross <colesbury@gmail.com>
Co-authored-by: Petr Viktorin <encukou@gmail.com>

Python/sysmodule.c

@@ -1183,9 +1183,10 @@ sys__settraceallthreads(PyObject *module, PyObject *arg)
         argument = arg;
     }
 
-
-    PyEval_SetTraceAllThreads(func, argument);
-
+    PyInterpreterState *interp = _PyInterpreterState_GET();
+    if (_PyEval_SetTraceAllThreads(interp, func, argument) < 0) {
+        return NULL;
+    }
     Py_RETURN_NONE;
 }
 
@@ -1263,8 +1264,10 @@ sys__setprofileallthreads(PyObject *module, PyObject *arg)
         argument = arg;
     }
 
-    PyEval_SetProfileAllThreads(func, argument);
-
+    PyInterpreterState *interp = _PyInterpreterState_GET();
+    if (_PyEval_SetProfileAllThreads(interp, func, argument) < 0) {
+        return NULL;
+    }
     Py_RETURN_NONE;
 }