This replaces uses of last_stmt where we do not require debug skipping

This replaces uses of last_stmt where we do not require debug skipping

There are quite some cases which want to access the control stmt
ending a basic-block.  Since there cannot be debug stmts after
such stmt there's no point in using last_stmt which skips debug
stmts and can be a compile-time hog for larger testcases.

	* gimple-ssa-split-paths.cc (is_feasible_trace): Avoid
	last_stmt.
	* graphite-scop-detection.cc (single_pred_cond_non_loop_exit):
	Likewise.
	* ipa-fnsummary.cc (set_cond_stmt_execution_predicate): Likewise.
	(set_switch_stmt_execution_predicate): Likewise.
	(phi_result_unknown_predicate): Likewise.
	* ipa-prop.cc (compute_complex_ancestor_jump_func): Likewise.
	(ipa_analyze_indirect_call_uses): Likewise.
	* predict.cc (predict_iv_comparison): Likewise.
	(predict_extra_loop_exits): Likewise.
	(predict_loops): Likewise.
	(tree_predict_by_opcode): Likewise.
	* gimple-predicate-analysis.cc (predicate::init_from_control_deps):
	Likewise.
	* gimple-pretty-print.cc (dump_implicit_edges): Likewise.
	* tree-ssa-phiopt.cc (tree_ssa_phiopt_worker): Likewise.
	(replace_phi_edge_with_variable): Likewise.
	(two_value_replacement): Likewise.
	(value_replacement): Likewise.
	(minmax_replacement): Likewise.
	(spaceship_replacement): Likewise.
	(cond_removal_in_builtin_zero_pattern): Likewise.
	* tree-ssa-reassoc.cc (maybe_optimize_range_tests): Likewise.
	* tree-ssa-sccvn.cc (vn_phi_eq): Likewise.
	(vn_phi_lookup): Likewise.
	(vn_phi_insert): Likewise.
	* tree-ssa-structalias.cc (compute_points_to_sets): Likewise.
	* tree-ssa-threadbackward.cc (back_threader::maybe_thread_block):
	Likewise.
	(back_threader_profitability::possibly_profitable_path_p):
	Likewise.
	* tree-ssa-threadedge.cc (jump_threader::thread_outgoing_edges):
	Likewise.
	* tree-switch-conversion.cc (pass_convert_switch::execute):
	Likewise.
	(pass_lower_switch<O0>::execute): Likewise.
	* tree-tailcall.cc (tree_optimize_tail_calls_1): Likewise.
	* tree-vect-loop-manip.cc (vect_loop_versioning): Likewise.
	* tree-vect-slp.cc (vect_slp_function): Likewise.
	* tree-vect-stmts.cc (cfun_returns): Likewise.
	* tree-vectorizer.cc (vect_loop_vectorized_call): Likewise.
	(vect_loop_dist_alias_call): Likewise.