The recent combining of complex part loads to a complex load missed
to account for non-call EH.

	PR tree-optimization/109262
	* tree-ssa-forwprop.cc (pass_forwprop::execute): When
	combining a piecewise complex load avoid touching loads
	that throw internally.  Use fun, not cfun throughout.

	* g++.dg/torture/pr109262.C: New testcase.