Run `integrity_test` in Externalities (#14546)

* Run integrity_test in RO externalities

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* frame-support: Export RO externalities

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Fix bench tests

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Update docs

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Rename to __private

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Run in TestExternalities

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Fix other pallets

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Update docs

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Fixes

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

* Update frame/support/src/dispatch.rs

Co-authored-by: Muharem Ismailov <ismailov.m.h@gmail.com>

* Fixup merge

Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>

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Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: parity-processbot <>
Co-authored-by: Muharem Ismailov <ismailov.m.h@gmail.com>