[Ada] Major code cleanup

[Ada] Major code cleanup

2018-07-16  Ed Schonberg  <schonberg@adacore.com>

gcc/ada/

	* einfo.adb (Set_Is_Uplevel_Referenced_Entity): Flag can appear on
	loop parameters.
	* exp_ch7.adb (Check_Unnesting_Elaboration_Code): Handle subprogram
	bodies.
	* exp_ch9.adb (Reset_Scopes_To): Set the scopes of entities local to an
	entry body to be the corresponding generated subprogram, for correct
	analysis of uplevel references.
	* exp_unst.adb (Visit_Node): Handle properly binary and unary operators
	Ignore pragmas, fix component associations.
	(Register_Subprograms): Subprograms in synchronized types must be
	treated as reachable.

From-SVN: r262723