Touch up the driver code in a couple of places

[potocnyj]

Switches an Sprint for the faster strconv call, and add support for
uint64 vals in the interpolation code

[Preetam]

Do the tests pass? If so, 👍.

[potocnyj]

Yeah, they pass

[potocnyj]

Looks like support for uint64 with high-bit set does not work without a prepared statement. I added this code to TestUint64:

runTests(t, dsn+"&interpolateParams=true", func(dbt *DBTest) {
        row := dbt.db.QueryRow(`SELECT ?, ?, ? ,?, ?, ?, ?, ?`,
            u0, uhigh, utop, uall,
            s0, shigh, stop, sall,
        )

        var ua, ub, uc, ud uint64
        var sa, sb, sc, sd int64

        err := row.Scan(&ua, &ub, &uc, &ud, &sa, &sb, &sc, &sd)
        if err != nil {
            dbt.Fatal(err)
        }
        switch {
        case ua != u0,
            ub != uhigh,
            uc != utop,
            ud != uall,
            sa != s0,
            sb != shigh,
            sc != stop,
            sd != sall:
            dbt.Fatal("Unexpected result value")
        }
    })

And the test fails with the following output:

--- FAIL: TestUint64 (0.00 seconds)
    driver_test.go:836: sql: converting Exec argument #2's type: uint64 values with high bit set are not supported

Not sure what is going on here yet, I'll update if I figure it out.

[gkristic]

I think we should open a PR upstream and contribute with the change.

[potocnyj]

I'll do so once I get an answer on the intended behavior of the support for uint64 params, it could affect the validity of what I did