[gtk/constraint-flexible-space] Make the testsuite pass

[Matthias Clasen <matthiasc src gnome org>]

commit a2bb1e6f13a413ff8e9549784eca5d82bcdae2a4
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Jun 26 05:15:40 2019 +0000

    Make the testsuite pass
    
    We were crashing while finalizing the solver.

 gtk/gtkconstraintsolver.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/gtk/gtkconstraintsolver.c b/gtk/gtkconstraintsolver.c
index 53262b70af..4186315ecf 100644
--- a/gtk/gtkconstraintsolver.c
+++ b/gtk/gtkconstraintsolver.c
@@ -265,6 +265,7 @@ gtk_constraint_solver_finalize (GObject *gobject)
 {
   GtkConstraintSolver *self = GTK_CONSTRAINT_SOLVER (gobject);
 
+  g_hash_table_remove_all (self->constraints);
   g_clear_pointer (&self->constraints, g_hash_table_unref);
 
   g_clear_pointer (&self->stay_error_vars, g_ptr_array_unref);