The tests were not running in CI on the experimental
branch which was an oversight and allowed for various
tests to fail. Now that experimental has been renamed
to regenesis/0.5.0, the tests are running in CI again.
This commit fixes all tests that were broken while
development happened on experimental.

It removes a config option `--rollup.minl2gaslimit`
that is no longer required post regenesis.

It also adds the ability to populate a genesis account
with value in the sync service tests.

* pkg: import l2geth

* chore: add l2geth tests submodule

* ci: unit test l2geth

* chore: skip Android tests

* chore: cleanup ci