re PR sanitizer/64717 (-fsanitize=vptr leads to warning: ‘<anonymous>’ may be used uninitialized in this function [-Wmaybe-uninitialized])

	PR c++/64717
	* cp-ubsan.c (cp_ubsan_instrument_vptr): Don't wrap vptr
	into SAVE_EXPR.

	* g++.dg/ubsan/pr64717-1.C: New test.
	* g++.dg/ubsan/pr64717-2.C: New test.

From-SVN: r220262