[NOT-FOR-MERGE] Test simdjson and broken stream

[yumkam]

Changelog entry

...

Changelog category

• New feature
• Experimental feature
• Improvement
• Performance improvement
• User Interface
• Bugfix
• Backward incompatible change
• Documentation (changelog entry is not required)
• Not for changelog (changelog entry is not required)

Description for reviewers

This code demonstrate lack of validation in json parsing in row dispatcher. We feed intentionally incorrect events (split by random boundary instead of json boundary), still rd parser accept them as correct.
I don't think this needs to be fixed (besides, simdjson parser is designed to accept specially crafted invalid json), but still.

[github-actions]

🟢 2025-07-21 18:14:32 UTC The validation of the Pull Request description is successful.

[github-actions]

⚪ 2025-07-22 14:54:41 UTC Pre-commit check linux-x86_64-relwithdebinfo for 2169a12 has started.
⚪ 2025-07-22 14:54:45 UTC Artifacts will be uploaded here
⚪ 2025-07-22 14:57:12 UTC ya make is running...
🟢 2025-07-22 15:21:18 UTC Tests successful.

Test history | Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
189	181	0	0	8	0

🟢 2025-07-22 15:21:26 UTC Build successful.
🟢 2025-07-22 15:21:36 UTC ydbd size 2.2 GiB changed* by +27.0 KiB, which is < 100.0 KiB vs main: OK

ydbd size dash	main: 4542c8b	merge: 2169a12	diff	diff %
ydbd size	2 397 969 328 Bytes	2 397 996 952 Bytes	+27.0 KiB	+0.001%
ydbd stripped size	501 472 680 Bytes	501 475 752 Bytes	+3.0 KiB	+0.001%

^{*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]

⚪ 2025-07-22 14:54:42 UTC Pre-commit check linux-x86_64-release-asan for 2169a12 has started.
⚪ 2025-07-22 14:54:46 UTC Artifacts will be uploaded here
⚪ 2025-07-22 14:57:17 UTC ya make is running...
🟢 2025-07-22 15:19:14 UTC Tests successful.

Test history | Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
31	31	0	0	0	0

🟢 2025-07-22 15:19:21 UTC Build successful.
🟢 2025-07-22 15:19:37 UTC ydbd size 3.9 GiB changed* by +26.2 KiB, which is < 100.0 KiB vs main: OK

ydbd size dash	main: 4542c8b	merge: 2169a12	diff	diff %
ydbd size	4 215 984 632 Bytes	4 216 011 504 Bytes	+26.2 KiB	+0.001%
ydbd stripped size	1 461 077 976 Bytes	1 461 098 328 Bytes	+19.9 KiB	+0.001%

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