Keep URI parameters when cipher_migrate reopens the main database - #629

PRAGMA cipher_migrate reopens the main database by sqlite3_db_filename(db, "main") without SQLITE_OPEN_URI. That name is the pager's own filename, so when the database was opened through a URI such as file:test.db?psow=0 its parameters follow the terminator and the VFS is told to ignore them. A SQLITE_DEBUG build aborts in unixOpen on the assertion that guards this, and a release build migrates but drops the parameters the VFS reads at open time, so psow=0 is lost after migration.

Adding SQLITE_OPEN_URI to both reopens, the normal one and the one in the error handler, is always valid for a name the pager produced. A name without parameters is double-zero terminated, so it behaves exactly as before.

The new tests migrate the 3.0 and 4.0 fixtures opened with psow=0, plus the error-handler path through fail_migrate_closed, and check the row count and that psow stays off. They fail on beta in both debug and release builds.