rtl-ssa: Don't insert after insns that can throw

rtl-ssa: Don't insert after insns that can throw

rtl_ssa::can_insert_after didn't handle insns that can throw.
Fixing that avoids a regression with a later patch.

gcc/
	* rtl-ssa.h: Include cfgbuild.h.
	* rtl-ssa/movement.h (can_insert_after): Replace is_jump with the
	more comprehensive control_flow_insn_p.