The `withFixtures` helper will instantiate ganache, a web driver, and
a fixture server initialized with the given set of fixtures. It is
meant to facilitating writing small, isolated e2e tests.
The first example test has been added: simple-send. It ensures that the
user can send 1 ETH to another account.
These new e2e tests will run during the normal e2e test run.
Closes#6548
