Implement runtime version checks in set_code (#4548)

* Implement runtime version checks in `set_code`

Check that the new runtime code given to `set_code` fullfills some
requirements:

- `spec_name` matches
- `spec_version` does not decreases
- `impl_version` does not decreases
- Either `spec_version` and `impl_version` increase

* Make tests almost work

* Some fixes after master merge

* Fix tests

* Add missed file

* Make depedency check happy?

* Remove leftover `sc-executor`

* AHHHHH

* Reset debug stuff

* Remove some 'static

* More 'static

* Some docs

* Update `Cargo.lock`

substrate/frame/system/Cargo.toml

@@ -18,6 +18,8 @@ impl-trait-for-tuples = "0.1.3"
 
 [dev-dependencies]
 criterion = "0.2.11"
+sp-externalities = { version = "0.8.0", path = "../../primitives/externalities" }
+substrate-test-runtime-client = { version = "2.0.0", path = "../../test-utils/runtime/client" }
 
 [features]
 default = ["std"]