Deprecate for removal AbstractBrowserTestBase::assertEquals(WebElement, WebElement)

[joelpop]

AbstractBrowserTestBase::assertEquals(WebElement, WebElement) should be deprecated as it is an obsolete workaround for TestBenchElement that formerly lacked an implementation for equals to correctly compare "wrapped" elements. That issue was resolved with the closing of TestBenchElement should implement equals on 10/21/2016.

Additional rationale for removing this method is due to its name collision with the JUnit5 assertion. Its presence in the base class with this name makes it impossible to statically import the JUnit5 assertEquals method in any test class—a big faux pas. Although deprecating does not resolve that issue, it sets the stage for its removal. Due to this method being protected, documented as a temporary workaround, and no longer be needed (per its Javadoc comment, below), it's removal makes sense.

The only currently known Vaadin usage of this method is in ShortcutsIT in the Flow repo.