Polysat: conflict resolution wip (#5529)

* conflict_core doesn't need gc() anymore

* update comments, ensure_bvar for new constraints

* Make sure constraints can only be created through constraint_manager

* fix constraint::display if no boolean variable is assigned

* Move clause into separate file

* Add conflict_core binary resolution

* conflict_core additions

* reactivate conflict resolution outer loop

* wip

* seems commented includes break CI build

src/math/polysat/variable_elimination.cpp

@@ -0,0 +1,19 @@
+/*++
+Copyright (c) 2021 Microsoft Corporation
+
+Module Name:
+
+    Polysat variable elimination
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2021-03-19
+    Jakob Rath 2021-04-6
+
+--*/
+#include "math/polysat/variable_elimination.h"
+
+namespace polysat {
+
+
+}