PR c++/95768 - pretty-printer ICE on -Wuninitialized with allocated storage

gcc/c-family/ChangeLog:

	PR c++/95768
	* c-pretty-print.c (c_pretty_printer::primary_expression): For
	SSA_NAMEs print VLA names and GIMPLE defining statements.
	(print_mem_ref): New function.
	(c_pretty_printer::unary_expression): Call it.

gcc/cp/ChangeLog:

	PR c++/95768
	* error.c (dump_expr): Call c_pretty_printer::unary_expression.

gcc/testsuite/ChangeLog:

	PR c++/95768
	* g++.dg/pr95768.C: New test.
	* g++.dg/warn/Wuninitialized-12.C: New test.
	* gcc.dg/uninit-38.c: New test.