MacGui tests: Remove references to CGPostMouseEvent

CGPostMouseEvent is obsolete and known to have "undocumented special
cases and undesirable side effects." The newer Quatz API doesn't
allow neither multiple mouse button events nor preserving the mouse
cursor location.

Change-Id: I121b02fd01e2990488b05e45431cbdc13589656e
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>
Cocoa: Fix mouse event coordinates transform to window space

We pass the mouse screen coordinates that we convert to window
space instead of the other way around. This makes sure the original
mouse coordinates are not bound to any moving window.

Task-number: QTBUG-29583
Task-number: QTBUG-32221
Change-Id: I8f9ada6e8c0d20af8e85e88ee39190d23e58977f
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>