Add mmap.MAP_POPULATE from 3.10 (#6964)

Author: versusvoid

stdlib/mmap.pyi

@@ -13,6 +13,8 @@ ALLOCATIONGRANULARITY: int
 if sys.platform == "linux":
     MAP_DENYWRITE: int
     MAP_EXECUTABLE: int
+    if sys.version_info >= (3, 10):
+        MAP_POPULATE: int
 
 if sys.platform != "win32":
     MAP_ANON: int

tests/stubtest_allowlists/linux-py310.txt

@@ -20,7 +20,6 @@ select.epoll.register
 # Exists at runtime, but missing from stubs
 asyncio.PidfdChildWatcher
 asyncio.unix_events.PidfdChildWatcher
-mmap.MAP_POPULATE
 os.EFD_CLOEXEC
 os.EFD_NONBLOCK
 os.EFD_SEMAPHORE