Changes according Dominic's review notes:
- xfoo and XFoo replaced by more informative names
- generate_tests replaced by loops
- use assert-throws
- code formatting
Creating and passing registries tests
Template test fixed
Changes according Dominic's review notes:
- use assert_unreached
- for() loops replaced by .forEach()
- more informative variables naming
- code formatting
- tests for template element registry removed
Custom elements lificycle tests
Changes according Dominic's review notes:
- more informative summary text
- code formatting
- FIXME comments added
No actual change just code formatting
Assertion text changed
Callback tests changes according to the Dominic:
- Check for callback arguments added
- tested different ways of setting and changing attribute value
- more informative assertion texsts
- code styling
More prototype tests
More custom elements naming tests
More registry tests and chenges in the assertion texts
Only files reviewed by Dominic left