I cannot reproduce this on my Ubuntu 20.04:

➜  cpython git:(master) ✗ LSAN_OPTIONS="suppressions=asan-suppression.txt,print_suppressions=0" ./python -m test -v test_eof
Modules/posixmodule.c:14682:9: runtime error: left shift of 34 by 26 places cannot be represented in type 'int'
== CPython 3.10.0a0 (heads/master:e2fb8a2c42, Jun 12 2020, 16:59:27) [GCC 9.3.0]
== Linux-5.4.0-33-generic-x86_64-with-glibc2.31 little-endian
== cwd: /home/lysnikolaou/repos/cpython/build/test_python_71258
== CPU count: 4
== encodings: locale=UTF-8, FS=utf-8
0:00:00 load avg: 2.11 Run tests sequentially
0:00:00 load avg: 2.11 [1/1] test_eof
test_EOFC (test.test_eof.EOFTestCase) ... ok
test_EOFS (test.test_eof.EOFTestCase) ... ok
test_eof_with_line_continuation (test.test_eof.EOFTestCase) ... ok
test_line_continuation_EOF (test.test_eof.EOFTestCase)
A continuation at the end of input must be an error; bpo2180. ... ok
test_line_continuation_EOF_from_file_bpo2180 (test.test_eof.EOFTestCase)
Ensure tok_nextc() does not add too many ending newlines. ... Modules/posixmodule.c:14682:9: runtime error: left shift of 34 by 26 places cannot be represented in type 'int'
ok

----------------------------------------------------------------------

Ran 5 tests in 0.413s

OK

== Tests result: SUCCESS ==

1 test OK.

Total duration: 654 ms
Tests result: SUCCESS