c++: Elide calls to NOP module initializers

c++: Elide calls to NOP module initializers

	gcc/cp
	* cp-tree.h (fini_modules): Add has_inits parm.
	* decl2.cc (c_parse_final_cleanups): Check for
	inits, adjust fini_modules flags.
	* module.cc (module_state): Rename call_init_p to
	active_init_p.
	(module_state::write_config): Write active_init.
	(module_state::read_config): Read it.
	(module_determine_import_inits): Clear active_init_p
	of covered inits.
	(late_finish_module): Add has_init parm.  Record it.
	(fini_modules): Adjust.

	gcc/testsuite/
	* g++.dg/modules/init-2_a.C: Adjust.
	* g++.dg/modules/init-2_c.C: Adjust.
	* g++.dg/modules/init-2_d.C: New.