fix: database/sql.Scanner should not retain references

[ncruces]

• Do only one thing
• Non breaking API changes
• Tested

What did this pull request do?

Documentation for database/sql.Scanner states that Scan(src) should not retain (i.e. it should copy) the src argument.

// Reference types such as []byte are only valid until the next call to Scan
// and should not be retained. Their underlying memory is owned by the driver.
// If retention is necessary, copy their values before the next call to Scan.

This becomes an issue for this test if a driver returns a slice that is invalidated by rows.Close().

User Case Description

Copying the slice fixes this test failing with my SQLite driver.