[Ada] Errors in handling of access_to_subprogram contracts

[Ada] Errors in handling of access_to_subprogram contracts

gcc/ada/

	* exp_ch3.adb (Build_Access_Subprogram_Wrapper_Body): Create
	proper subprogram specification for body, using names in the
	subprogram declaration but distinct entities.
	* exp_ch6.adb (Expand_Call): If this is an indirect call
	involving a subprogram wrapper, insert pointer parameter in list
	of actuals with a parameter association, not as a positional
	parameter.