Remove PHI_RESULT_PTR and change some PHI_RESULT to be gimple_phi_result [PR116643]

Remove PHI_RESULT_PTR and change some PHI_RESULT to be gimple_phi_result [PR116643]

There was only a few uses PHI_RESULT_PTR so lets remove it and use gimple_phi_result_ptr
or gimple_phi_result directly instead.
Since I was modifying ssa-iterators.h for the use of PHI_RESULT_PTR, change the use
of PHI_RESULT there to be gimple_phi_result instead.

This also removes one extra indirection that was done for PHI_RESULT so stage2 building
should be slightly faster.

Bootstrapped and tested on x86_64-linux-gnu.

	PR middle-end/116643

gcc/ChangeLog:

	* ssa-iterators.h (single_phi_def): Use gimple_phi_result
	instead of PHI_RESULT.
	(op_iter_init_phidef): Use gimple_phi_result/gimple_phi_result_ptr
	instead of PHI_RESULT/PHI_RESULT_PTR.
	* tree-ssa-operands.h (PHI_RESULT_PTR): Remove.
	(PHI_RESULT): Use gimple_phi_result directly.
	(SET_PHI_RESULT): Use gimple_phi_result_ptr directly.

Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>