e2e beta test upgrades for confirm refactor

[danjm]

This PR makes a number of improvements to the e2e tests, while also making specific changes needed for the confirm refactor.

The general improvements include:

• replacing reliance on external urls for tests of external dapp behaviour with a locally served dapp
• replacing the assumption that webdriver's getAllWindowHandles method returns window handles in the order that they are opened. Instead, windows are selected by conditions that specifically identify the window we are looking for
• adds a helper method for asserting that elements are not found in the dom
• adds helper methods for selecting windows by document title and closing windows other than those specified

Confirm refactor specific updates include:

• testing of erc20 "Approve" confirmations
• testing the new data tab on the confirm screen
• testing that contract creation data is as expected
• updates to meeting the new confirm ui

This PR also includes updates to the integration tests to ensure they pass given updates to confirm screen html/css and updates to how the routing system handles unapproved transactions

[metamaskbot]

Builds ready [07322bc]: mascara, chrome, firefox, edge, opera