[3.11] gh-108303: Fix and move badsyntax_pep3120.py (GH-109513)

[sobolevn]

(cherry picked from commit 4dd47c6)

• Issue: Move test files into test subdirectories #108303

[vstinner]

Tests fail:

ERROR: test_find_module_encoding (test.test_imp.ImportTests.test_find_module_encoding)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/runner/work/cpython/cpython-ro-srcdir/Lib/test/test_imp.py", line 83, in test_find_module_encoding
    imp.find_module('badsyntax_pep3120', path)
  File "/home/runner/work/cpython/cpython-ro-srcdir/Lib/imp.py", line 297, in find_module
    raise ImportError(_ERR_MSG.format(name), name=name)
ImportError: No module named 'badsyntax_pep3120'

[sobolevn]

test_imp is missing in 3.12 and 3.13, fixed 👍

[ambv]

There's still three failures that survive re-runs:

ERROR: test_inline_table_recursion_limit (test.test_tomllib.test_misc.TestMiscellaneous.test_inline_table_recursion_limit) (limit=137, available=99, nest_count=32)
FAIL: test_get_recursion_depth (test.test_support.TestSupport.test_get_recursion_depth)
 ERROR: test_recursion (test.test_support.TestSupport.test_recursion)

All are about exceeded recursion limits.

[AlexWaygood]

ERROR: test_inline_table_recursion_limit (test.test_tomllib.test_misc.TestMiscellaneous.test_inline_table_recursion_limit) (limit=137, available=99, nest_count=32)

That one's been failing on the 3.11 branch for a while now, I think, FWIW. Don't know about the others.

[vstinner]

ERROR: test_inline_table_recursion_limit (test.test_tomllib.test_misc.TestMiscellaneous.test_inline_table_recursion_limit) (limit=137, available=99, nest_count=32)
FAIL: test_get_recursion_depth (test.test_support.TestSupport.test_get_recursion_depth)
ERROR: test_recursion (test.test_support.TestSupport.test_recursion)

Sadly, these ones are regressions when I fixed a RecursionError :-( See issue GH-108851.