Sync pre-release CPython main branch from GitHub (2026-08-13)

Summary:
Imported python/cpython `3.16.0a0` from upstream rev [`ee4fe00`](https://www.github.com/python/cpython/commit/ee4fe00a8f72ea84a421bb626d7c78335c5c9ea1) (committed 2026-08-13 00:12:39+00:00).

# Commit Info

- Base: (`3.16.0a0`) - [`ee68f5f`](https://www.github.com/python/cpython/commit/ee68f5f46a14e2bbf22d72796e45e5f467951792) (commit date: 2026-08-11 23:16:05+00:00)
- Imported: (`3.16.0a0`) - [`ee4fe00`](https://www.github.com/python/cpython/commit/ee4fe00a8f72ea84a421bb626d7c78335c5c9ea1) (commit date: 2026-08-13 00:12:39+00:00)

# Noteworthy file changes

- Native files (1 added):
  ```
  + Modules/_testlimitedcapi/type.c
  ```
- Low-signal files (6 added) (NEWS.d, docs, .github)

Complete list of added/removed files: https://www.internalfb.com/intern/everpaste/?color=0&handle=GA3qBC4DBoV2XdYEAKJh7cHWUH8Pbr0LAAAz

Reviewed By: ambv

Differential Revision: D115830379

fbshipit-source-id: f1747c799ca725bf5487ca2ea5e466e1a86105e8

Author: itamaro

cinderx/Interpreter/3.16/Includes/Python/ceval_macros.h

@@ -354,6 +354,25 @@ static void dtrace_function_return(_PyInterpreterFrame *);
 #define ADAPTIVE_COUNTER_TRIGGERS(COUNTER) \
     backoff_counter_triggers(forge_backoff_counter((COUNTER)))
 
+#ifdef Py_GIL_DISABLED
+/* Counters are unreachable when thread-local bytecode is disabled,
+ * so there is no need to update them. */
+#define ADVANCE_ADAPTIVE_COUNTER(COUNTER) \
+    do { \
+        _Py_BackoffCounter cnt = (COUNTER); \
+        if (!backoff_counter_is_unreachable(cnt)) { \
+            (COUNTER) = advance_backoff_counter(cnt); \
+        } \
+    } while (0);
+
+#define PAUSE_ADAPTIVE_COUNTER(COUNTER) \
+    do { \
+        _Py_BackoffCounter cnt = (COUNTER); \
+        if (!backoff_counter_is_unreachable(cnt)) { \
+            (COUNTER) = pause_backoff_counter(cnt); \
+        } \
+    } while (0);
+#else
 #define ADVANCE_ADAPTIVE_COUNTER(COUNTER) \
     do { \
         (COUNTER) = advance_backoff_counter((COUNTER)); \
@@ -363,6 +382,7 @@ static void dtrace_function_return(_PyInterpreterFrame *);
     do { \
         (COUNTER) = pause_backoff_counter((COUNTER)); \
     } while (0);
+#endif
 
 #ifdef ENABLE_SPECIALIZATION
 /* Multiple threads may execute these concurrently if thread-local bytecode is