gh-128031: Preserve tab characters in untokenize()

[tomasr8]

• Issue: untokenize() does not round-trip for tab characters #128031

[terryjreedy]

Address sanitizer failures are not obviously related to the patch.

2024-12-17T15:33:42.5746017Z 0:00:43 load avg: 4.13 [ 44/481/1] test_io failed (2 failures) (40.8 sec)
...
024-12-17T15:33:42.6481654Z ======================================================================
2024-12-17T15:33:42.6482722Z FAIL: test_daemon_threads_shutdown_stderr_deadlock (test.test_io.CMiscIOTest.test_daemon_threads_shutdown_stderr_deadlock)
2024-12-17T15:33:42.6483787Z ----------------------------------------------------------------------
2024-12-17T15:33:42.6484372Z Traceback (most recent call last):
2024-12-17T15:33:42.6485407Z   File "/home/runner/work/cpython/cpython/Lib/test/test_io.py", line 4646, in test_daemon_threads_shutdown_stderr_deadlock
2024-12-17T15:33:42.6486489Z     self.check_daemon_threads_shutdown_deadlock('stderr')
2024-12-17T15:33:42.6487092Z     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^
2024-12-17T15:33:42.6488126Z   File "/home/runner/work/cpython/cpython/Lib/test/test_io.py", line 4636, in check_daemon_threads_shutdown_deadlock
2024-12-17T15:33:42.6489050Z     self.assertFalse(err.strip('.!'))
2024-12-17T15:33:42.6489524Z     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
2024-12-17T15:33:42.6491363Z AssertionError: '=================================================================\n==11509==ERROR: AddressSanitizer: heap-use-after-free on address 0x513000068258 at pc 0x563d2271f3a5 bp 0x7f72d71ff1e0 sp 0x7f72d71ff1d0\nREAD of size 8 at 0x513000068258 thread T1\n' is not false
2024-12-17T15:33:42.6492683Z 
2024-12-17T15:33:42.6492912Z ======================================================================
2024-12-17T15:33:42.6493979Z FAIL: test_daemon_threads_shutdown_stdout_deadlock (test.test_io.CMiscIOTest.test_daemon_threads_shutdown_stdout_deadlock)
2024-12-17T15:33:42.6495035Z ----------------------------------------------------------------------
2024-12-17T15:33:42.6495599Z Traceback (most recent call last):
2024-12-17T15:33:42.6496620Z   File "/home/runner/work/cpython/cpython/Lib/test/test_io.py", line 4641, in test_daemon_threads_shutdown_stdout_deadlock
2024-12-17T15:33:42.6497686Z     self.check_daemon_threads_shutdown_deadlock('stdout')
2024-12-17T15:33:42.6498489Z     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^
2024-12-17T15:33:42.6499511Z   File "/home/runner/work/cpython/cpython/Lib/test/test_io.py", line 4636, in check_daemon_threads_shutdown_deadlock
2024-12-17T15:33:42.6500623Z     self.assertFalse(err.strip('.!'))
2024-12-17T15:33:42.6501086Z     ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
2024-12-17T15:33:42.6502721Z AssertionError: '=================================================================\n==11551==ERROR: AddressSanitizer: heap-use-after-free on address 0x513000068258 at pc 0x5645866a73a5 bp 0x7fd32d1ff1e0 sp 0x7fd32d1ff1d0\nREAD of size 8 at 0x513000068258 thread T1\n' is not false
...
2024-12-17T15:35:24.6647789Z 0:02:25 load avg: 5.74 [214/481/2] test_threading failed (1 failure) (43.8 sec)
...
2024-12-17T15:35:24.7390166Z FAIL: test_4_daemon_threads (test.test_threading.ThreadJoinOnShutdown.test_4_daemon_threads)
2024-12-17T15:35:24.7391136Z ----------------------------------------------------------------------
2024-12-17T15:35:24.7391733Z Traceback (most recent call last):
2024-12-17T15:35:24.7392657Z   File "/home/runner/work/cpython/cpython/Lib/test/test_threading.py", line 1403, in test_4_daemon_threads
2024-12-17T15:35:24.7393548Z     self.assertFalse(err)
2024-12-17T15:35:24.7393936Z     ~~~~~~~~~~~~~~~~^^^^^
2024-12-17T15:35:24.7395533Z AssertionError: b'=================================================================\n==13911==ERROR: AddressSanitizer: heap-use-after-free on address 0x513000026698 at pc 0x563d095193a5 bp 0x7f2e6e7fefd0 sp 0x7f2e6e7fefc0\nREAD of size 8 at 0x513000026698 thread T36\n' is not false

Thread sanitizer failures are not obviously related to the patch.

2024-12-17T15:35:01.6725009Z 0:01:54 load avg: 6.14 [ 9/23/1] test_importlib failed (1 failure) (1 min 34 sec) -- running (2): test_io (1 min 15 sec), test_queue (1 min 5 sec)
2024-12-17T15:35:01.6733903Z test test_importlib failed -- Traceback (most recent call last):
2024-12-17T15:35:01.6738465Z   File "/home/runner/work/cpython/cpython/Lib/test/test_importlib/test_threaded_import.py", line 255, in test_multiprocessing_pool_circular_import
2024-12-17T15:35:01.6743402Z     script_helper.assert_python_ok(fn)
2024-12-17T15:35:01.6747034Z     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^
2024-12-17T15:35:01.6751016Z   File "/home/runner/work/cpython/cpython/Lib/test/support/script_helper.py", line 182, in assert_python_ok
2024-12-17T15:35:01.6755556Z     return _assert_python(True, *args, **env_vars)
2024-12-17T15:35:01.6760208Z   File "/home/runner/work/cpython/cpython/Lib/test/support/script_helper.py", line 167, in _assert_python
2024-12-17T15:35:01.6763424Z     res.fail(cmd_line)
2024-12-17T15:35:01.6764935Z     ~~~~~~~~^^^^^^^^^^
2024-12-17T15:35:01.6766715Z   File "/home/runner/work/cpython/cpython/Lib/test/support/script_helper.py", line 80, in fail
2024-12-17T15:35:01.6768054Z     raise AssertionError(f"Process return code is {exitcode}\n"
2024-12-17T15:35:01.6768806Z     ...<10 lines>...
2024-12-17T15:35:01.6769706Z                          f"---")
2024-12-17T15:35:01.6773736Z AssertionError: Process return code is 66

2024-12-17T15:36:20.4761430Z 0:03:12 load avg: 6.17 [14/23/2] test_ssl failed (env changed) (39.0 sec) -- running (2): test_socket (1 min 18 sec), test_queue (2 min 23 sec)
2024-12-17T15:36:20.4768670Z Warning -- warnings.filters was modified by test_ssl
2024-12-17T15:36:20.4769185Z Warning --   Before: (140304233595376, [], [])
2024-12-17T15:36:20.4769949Z Warning --   After:  (140302523435376, [('always', None, <class 'ResourceWarning'>, None, 0)], [('always', None, <class 'ResourceWarning'>, None, 0)])

I set these two tests to rerun.