re PR middle-end/51929 (ICE: verify_cgraph_node failed with -O2 -fno-guess-branch-probability -fipa-cp-clone)

	PR middle-end/51929
	* cgraphunit.c (verify_edge_corresponds_to_fndecl): If node is
	a same_body_alias, also test whether e->callee isn't a former
	or current clone of the decl this is a same body alias of.

	* g++.dg/ipa/pr51929.C: New test.

From-SVN: r184301