re PR tree-optimization/51596 (ICE: verify_flow_info failed: BB 6 can not throw but has an EH edge with -fnon-call-exceptions)

	PR tree-optimization/51596
	* tree-cfg.c (replace_uses_by): Call gimple_purge_dead_eh_edges
	when needed.

	* g++.dg/opt/pr51596.C: New test.

From-SVN: r182481