fix test in asan (nullptr possible in original data)

[ivanmorozov333]

• Bugfix

[github-actions]

⚪ 2024-07-06 08:57:49 UTC Pre-commit check for b81dcc2 has started.
⚪ 2024-07-06 09:00:17 UTC Build linux-x86_64-release-clang14 is running...
🟢 2024-07-06 09:07:19 UTC Build successful.

[github-actions]

⚪ 2024-07-06 08:58:19 UTC Pre-commit check for b81dcc2 has started.
⚪ 2024-07-06 09:01:04 UTC Build linux-x86_64-relwithdebinfo is running...
🟢 2024-07-06 09:39:25 UTC Build successful.
⚪ 2024-07-06 09:39:41 UTC Tests are running...
🔴 2024-07-06 11:09:00 UTC Some tests failed, follow the links below.

Test history | Test log

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
13870	12550	0	1	1307	12

🟢 2024-07-06 11:09:36 UTC ydbd size 8.1 GiB changed* by -200 Bytes, which is <= 0 Bytes vs main: OK

ydbd size dash	main: 1fa2be9	merge: b81dcc2	diff	diff %
ydbd size	8 721 818 088 Bytes	8 721 817 888 Bytes	-200 Bytes	-0.000%
ydbd stripped size	476 604 728 Bytes	476 604 728 Bytes	0 Bytes	0.000%

^{*please be aware that the difference is based on comparing your commit and the last completed build from the post-commit, check comparation}

[github-actions]

⚪ 2024-07-06 08:59:59 UTC Pre-commit check for b81dcc2 has started.
⚪ 2024-07-06 09:02:37 UTC Build linux-x86_64-release-asan is running...
🟢 2024-07-06 09:26:38 UTC Build successful.
⚪ 2024-07-06 09:26:54 UTC Tests are running...
🔴 2024-07-06 11:26:09 UTC Some tests failed, follow the links below.

Test history | Test log

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
9753	9177	0	82	321	173

🟢 2024-07-06 11:26:58 UTC ydbd size 5.2 GiB changed* by +80 Bytes, which is < 100.0 KiB vs main: OK

ydbd size dash	main: 1fa2be9	merge: b81dcc2	diff	diff %
ydbd size	5 614 212 624 Bytes	5 614 212 704 Bytes	+80 Bytes	+0.000%
ydbd stripped size	1 209 994 424 Bytes	1 209 994 424 Bytes	0 Bytes	0.000%

^{*please be aware that the difference is based on comparing your commit and the last completed build from the post-commit, check comparation}