This commit fixes a race condition in the
`attemptRestoreProjectStateForPaths` function that could cause a file to
be opened more than once within the same workspace pane.
In particular, when opening some file into an empty window, Atom tries
to recover the state for the project containing the file (if there is
one). However, we were previously not waiting until the
`AtomEnvironment`'s state had been fully deserialized before trying to
load the requested file into the workspace. If the same file also
existed in the serialized representation of the workspace, it could end
up being opened twice.
With this commit we will now wait until the environment has been fully
deserialized before honoring the user's request of loading new files
into an empty window. Also, tests have been restructured to test more
thoroughly this interaction.
