saveAppState needs to be called to perform the quit

[bsclifton]

saveAppState needs to be called to perform the quit
(was only missing from the lastWindowClosed case)

Unintentionally introduced with 40abc0c#diff-2018087f584c4398b5c3a23fc0e5f9dbR172
True needs to be passed, because the last known window state is saved, so receivedAllWindows is always false

Fixes #8629

Auditors: @bridiver
cc: @jonathansampson, @NejcZdovc

Submitter Checklist:

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Ran git rebase -i to squash commits (if needed).

Test Plan:

Reviewer Checklist:

Tests

• Adequate test coverage exists to prevent regressions
• Tests should be independent and work correctly when run indivually or as a suite ref