Make vectored read_blobs function not fill buffer correctly

[arpad-m]

There was barely any breakage in #8288 so I'm wondering whether pytests work at all for vectored reads.

This PR is meant to find that out: just break vectored reads completely.

DO NOT MERGE.

[github-actions]

No tests were run or test report is not available

Test coverage report is not available

_{The comment gets automatically updated with the latest test results
c0ae2c4 at 2024-07-09T16:29:17.172Z :recycle:}

[arpad-m]

There is a lot of failures. The reason why there isn't a test report is here:

Error: Unhandled error: HttpError: Validation Failed: {"resource":"IssueComment","code":"custom","field":"body","message":"body is too long (maximum is 65536 characters)"}

If you look at the logs manually, you see:

2024-07-10T02:25:27.2012222Z = 372 failed, 123 passed, 12 skipped, 448 errors, 94 rerun in 2144.25s (0:35:44) =

so safe to say, I think there is plenty of vectored read test coverage in the testsuite.

Closing as the experiment has concluded.