The parsing code used to access all kinds of stuff (e.g. the project
tree and the toolchain manager) from the non-UI thread, which is not
allowed.
Fixes: QTCREATORBUG-22420
Change-Id: I4be47919d7e543376d31826dd380f66f4e060458
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>
