[Ada] Diagnostics for Elaboration order v4.0

[Ada] Diagnostics for Elaboration order v4.0

This patch adds a missing case to the output of cycle diagnostics here a
transition from an Elaborate_Body pair may reach a destination which is
in the context of an active Elaborate_All.

2019-07-08  Hristian Kirtchev  <kirtchev@adacore.com>

gcc/ada/

	* bindo-diagnostics.adb (Diagnose_Cycle): Capture the presence
	of an Elaborate_All edge before iterating over the edges of the
	cycle.
	(Output_Elaborate_Body_Transition): Update the parameter profile
	and the comment on usage. Add a missing case where the edge is
	within the context of an Elaborate_All.
	(Output_Transition): Update the call to
	Output_Elaborate_Body_Transition.
	* bindo-graphs.ads, bindo-graphs.adb
	(Contains_Elaborate_All_Edge): New routine.

From-SVN: r273217