analyzer: tweaks to exploded_node ctor

I have followup work that touches this, so it's easiest to get this
cleanup in first.

gcc/analyzer/ChangeLog:
	* engine.cc (exploded_node::exploded_node): Move implementation
	here from header; accept point_and_state by const reference rather
	than by value.
	* exploded-graph.h (exploded_node::exploded_node): Pass
	point_and_state by const reference rather than by value.  Move
	body to engine.cc.

gcc/analyzer/ChangeLog

+2020-03-18  David Malcolm  <dmalcolm@redhat.com>
+
+	* engine.cc (exploded_node::exploded_node): Move implementation
+	here from header; accept point_and_state by const reference rather
+	than by value.
+	* exploded-graph.h (exploded_node::exploded_node): Pass
+	point_and_state by const reference rather than by value.  Move
+	body to engine.cc.
+
 2020-03-18  Jakub Jelinek  <jakub@redhat.com>
 
 	* sm-malloc.cc (malloc_state_machine::on_stmt): Fix up duplicated word

gcc/analyzer/engine.cc

@@ -795,6 +795,17 @@ print_enode_indices (pretty_printer *pp,
     }
 }
 
+/* class exploded_node : public dnode<eg_traits>.  */
+
+/* exploded_node's ctor.  */
+
+exploded_node::exploded_node (const point_and_state &ps,
+			      int index)
+: m_ps (ps), m_status (STATUS_WORKLIST), m_index (index)
+{
+  gcc_checking_assert (ps.get_state ().m_region_model->canonicalized_p ());
+}
+
 /* For use by dump_dot, get a value for the .dot "fillcolor" attribute.
    Colorize by sm-state, to make it easier to see how sm-state propagates
    through the exploded_graph.  */

gcc/analyzer/exploded-graph.h

@@ -175,12 +175,7 @@ class exploded_node : public dnode<eg_traits>
     STATUS_MERGER
   };
 
-  exploded_node (point_and_state ps,
-		 int index)
-  : m_ps (ps), m_status (STATUS_WORKLIST), m_index (index)
-  {
-    gcc_checking_assert (ps.get_state ().m_region_model->canonicalized_p ());
-  }
+  exploded_node (const point_and_state &ps, int index);
 
   hashval_t hash () const { return m_ps.hash (); }