Conform with standard History API

[PaperStrike]

Motivation and Context

• The initial value of window.history.state is null.
• replaceState and pushState make no use of "title" parameter in HTML Standard.
• Safari uses the title parameter to present the name of the history state in places like back button dropdown, and if we pass empty strings, Safari uses unlovely raw URLs. — Set the title of current history state at the end of preparePage.

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Refactor (no bug fix and new feature but improvements)

Checklist:

• My change requires new tests.
• I have added tests to cover my changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.