stdlib: Add os.pidfd_open(pid)

tests/stubtest_allowlists/linux-py310.txt

@@ -29,7 +29,6 @@ os.copy_file_range
 os.eventfd
 os.eventfd_read
 os.eventfd_write
-os.pidfd_open
 os.splice
 posix.EFD_[A-Z]+
 posix.SPLICE_[A-Z_]+
@@ -37,5 +36,4 @@ posix.copy_file_range
 posix.eventfd
 posix.eventfd_read
 posix.eventfd_write
-posix.pidfd_open
 posix.splice

tests/stubtest_allowlists/linux-py39.txt

@@ -3,6 +3,4 @@ select.epoll.register
 
 # Exists at runtime, but missing from stubs
 os.copy_file_range
-os.pidfd_open
 posix.copy_file_range
-posix.pidfd_open