TIL that 'go get example.com/foo' downloads only what the respective
package requires, but 'go mod tidy' will also download test-only
dependencies.

If needed, the CGo dependencies can be revived in a separate
repository/module. For now just delete it.

h/t: Dan Kortschak

use passed context in BeginTx

See merge request cznic/sqlite!71

Add support for setting SQLITE_FCNTL_PERSIST_WAL

See merge request cznic/sqlite!72