cpython test_pidfd_open requires SYS_pidfd_open support

[vtikoo]

This test has already been disabled for cpython 3.10 in d0e8f7b. Similar fix is needed for cpython 3.9.

[2023-07-25T08:21:02.161Z] �[0m*** kernel panic: syscall.c(7828): _syscall(): unknown syscall: SYS_pidfd_open(): 434
[2023-07-25T08:21:02.161Z] 0x100424c5c: __myst_panic()
[2023-07-25T08:21:02.161Z] 0x10040df3a: _syscall()
[2023-07-25T08:21:02.161Z] 0x100447152: __morestack()
[2023-07-25T08:21:02.161Z] Fatal Python error: Segmentation fault
[2023-07-25T08:21:02.161Z] 
[2023-07-25T08:21:02.161Z] Current thread 0x00000003036ebda8 (most recent call first):
[2023-07-25T08:21:02.161Z]   File "/cpython/Lib/test/test_posix.py", line 1486 in test_pidfd_open
[2023-07-25T08:21:02.161Z]   File "/cpython/Lib/unittest/case.py", line 550 in _callTestMethod
[2023-07-25T08:21:02.161Z]   File "/cpython/Lib/unittest/case.py", line 592 in run
[2023-07-25T08:21:02.161Z]   File "/cpython/Lib/unittest/case.py", line 651 in __call__
[2023-07-25T08:21:02.161Z]   File "/cpython/Lib/unittest/suite.py", line 122 in run
[2023-07-25T08:21:02.161Z]   File "/cpython/Lib/unittest/suite.py", line 84 in __call__
[2023-07-25T08:21:02.161Z]   File "/cpython/Lib/unittest/suite.py", line 122 in run
[2023-07-25T08:21:02.161Z]   File "/cpython/Lib/unittest/suite.py", line 84 in __call__
[2023-07-25T08:21:02.161Z]   File "/cpython/Lib/unittest/runner.py", line 176 in run
[2023-07-25T08:21:02.161Z]   File "/cpython/Lib/test/support/__init__.py", line 1826 in _run_suite
[2023-07-25T08:21:02.161Z]   File "/cpython/Lib/test/support/__init__.py", line 1950 in run_unittest
[2023-07-25T08:21:02.161Z]   File "/cpython/Lib/test/test_posix.py", line 2148 in test_main
[2023-07-25T08:21:02.161Z]   File "/cpython/Lib/test/libregrtest/runtest.py", line 288 in _runtest_inner2
[2023-07-25T08:21:02.162Z]   File "/cpython/Lib/test/libregrtest/runtest.py", line 326 in _runtest_inner
[2023-07-25T08:21:02.162Z]   File "/cpython/Lib/test/libregrtest/runtest.py", line 217 in _runtest
[2023-07-25T08:21:02.162Z]   File "/cpython/Lib/test/libregrtest/runtest.py", line 247 in runtest
[2023-07-25T08:21:02.162Z]   File "/cpython/Lib/test/libregrtest/main.py", line 434 in run_tests_sequential
[2023-07-25T08:21:02.162Z]   File "/cpython/Lib/test/libregrtest/main.py", line 532 in run_tests
[2023-07-25T08:21:02.162Z]   File "/cpython/Lib/test/libregrtest/main.py", line 705 in _main
[2023-07-25T08:21:02.162Z]   File "/cpython/Lib/test/libregrtest/main.py", line 652 in main
[2023-07-25T08:21:02.162Z]   File "/cpython/Lib/test/libregrtest/main.py", line 730 in main
[2023-07-25T08:21:02.162Z]   File "/cpython/Lib/test/__main__.py", line 2 in <module>
[2023-07-25T08:21:02.162Z]   File "/cpython/Lib/runpy.py", line 87 in _run_code
[2023-07-25T08:21:02.162Z]   File "/cpython/Lib/runpy.py", line 197 in _run_module_as_main
[2023-07-25T08:21:02.162Z] *** Kernel segmentation fault 
[2023-07-25T08:21:02.162Z] 0x1003e50c9: myst_signal_process()
[2023-07-25T08:21:02.162Z] 0x100447152: __morestack()