re PR c++/64433 (Segmentation fault while compiling)

re PR c++/64433 (Segmentation fault while compiling)

	cp/
	PR c++/64433
	DR1658, DR1611
	* init.c (emit_mem_initializers): Don't construct vbases of
	abstract classes.
	(push_base_cleanups): Don't push vbase cleanups for abstract class
	when in C++14 mode.
	* method.c (synthethesized_method_walk): Don't walk vbases of
	abstract classes when in C++14 mode.

	testsuite/
	PR c++/66443
	* g++.dg/cpp0x/pr66443-cxx11.C: New.
	* g++.dg/cpp0x/pr66443-cxx11-2.C: New.
	* g++.dg/cpp1y/pr66443-cxx14.C: New
	* g++.dg/cpp1y/pr66443-cxx14-2.C: New.
	* g++.dg/cpp1y/pr66443-cxx14-3.C: New.

From-SVN: r240874