Revert "Merge pull request #5569 from fungl164/fungl164/osx-livebrowser-fix"

This reverts commit d0ba7ec9f39a6348ea2a6c89d56efd6f353cf5ab, reversing
changes made to 8f5ccb4be26c69e1a7ce0aead02d00990711897e.
Merge pull request #5997 from adobe/jasonsanjose/revert-mac-chrome-sprint34

Revert changes to Chrome live preview on mac for sprint 34
Move async file.exists test out of EditorManager into DocumentCommandHandlers, to keep EditorManager’s chowCustomViewer and it’s affiliates synchronous.

At the same time this fixes unit tests that were broken by merging pull request 5910 / to fix 5742

However the original facet of bug 5742, where an image file is deleted while being viewed and then clicked on in the file tree is still not fixed, because the expectation is not accurate. When a file is deleted it stays in view, if you click on its file in the project tree it remains in view.

This fixes the case where you have an image file in the project tree that has been deleted from disk but you are looking at another file, either text or image. If you then click on a stale image the file open error will pop up.
changes due to review feedback
Merge pull request #6002 from adobe/couzteau/fix-5986

Fix Unit tests, Move async file.exists test out of EditorManager into DocumentCommandHandlers
Merge remote-tracking branch 'origin/master' into cmv4
update CodeMirror v4