1. `FetchMode::STANDARD_OBJECT` and `FetchMode::CUSTOM_OBJECT` are no longer supported.
2. `FetchMode::COLUMN` with a non-zero index is no longer supported.
3. Incompatible change in the `Connection::fetchColumn()` signature where the 3rd argument is now `$types`, not `$columnIndex`.

[DBAL-2958] Replaced extension of \PDOStatement with a composition to avoid having to replicate the \PDOStatement interface in ResultStatement

Fixes #2953.

Allows result sets to be iterated over without running out of memory on
large data sets.

Fix PSR2 rules : "As per PSR2, the static declaration should come after the visibility declaration."

1. Reworked the parser syntax to use proper Oracle escaping syntax as '' instead of \'.
2. Moved valid tests to the Functional section to ensure correct SQL syntax and logic.