Add a test for QuickOpen and a custom matcher for editor cursor position.

The QuickOpen test checks three things currently:

1. Ability to open a file with QuickOpen with the expected matching
2. Ability to jump to a line
3. The selected line is centered
change the FindReplace-test to use the toHaveCursorPosition matcher.
address review comments from @jasonsanjose.

This mostly consisted of removing code that I added while making the
test work in the first place and while working on mocks.
Merge pull request #2602 from adobe/dangoor/quickopentest

[cmv3] Adds an integration test for QuickOpen