row_count field to table

[Shubham8287]

Description of Changes

Meta data field in Table struct for row count.

API and ABI breaking changes

N/A

Expected complexity level and risk

*How complicated do you think these changes are? Grade on a scale from 1 to 5,
2

[gefjon]

Please add test(s) which exercise the following paths and assert the row count is correct:

• Inserts.
• Inserts followed by deletes.
• Insert of an already-present row, causing a set-semantic violation.
• core::db::datastore::locking_tx_datastore::mut_tx::MutTx::delete_by_row.
• Transaction replay.

[Shubham8287]

• core::db::datastore::locking_tx_datastore::mut_tx::MutTx::delete_by_row.

I didn't get what it means, considering row_count is only implemented for read tx. I may add test if you explain.

Added test for rest of the paths.