119981: stmtdiagnostics: reduce row count in a test r=yuzefovich a=yuzefovich

We can go from 10k to 100 for the large table while still getting the desired plans.

Informs: #119945

Epic: None

Release note: None

119986: sql: enhance error messages on validation of rows in virtual tables r=yuzefovich a=yuzefovich

We just saw an internal error when populating `crdb_internal.cluster_locks` virtual table that was missing important bits (the column name) to understand what happens. Since names of virtual tables and columns in them don't contain PII, they are safe for redaction.

Epic: None

Release note: None

Co-authored-by: Yahor Yuzefovich <yahor@cockroachlabs.com>