Remove VINSN_INSN_RTX scaffolding

Remove VINSN_INSN_RTX scaffolding

gcc/
	* sel-sched-ir.h (struct vinsn_def): Strengthen field "insn_rtx"
	from rtx to rtx_insn *.
        (VINSN_INSN_RTX): Eliminate rvalue function and...
	(SET_VINSN_INSN): ...lvalue function in favor of...
	(VINSN_INSN_RTX): reinstate this old macro.

	* sel-sched-ir.c (vinsn_init): Eliminate use of SET_VINSN_INSN_RTX
	in favor of VINSN_INSN_RTX.
	(VINSN_INSN_RTX): Delete this function.
	(SET_VINSN_INSN_RTX): Likewise.

/
	* rtx-classes-status.txt (TODO): Remove SET_VINSN_INSN_RTX.

From-SVN: r214529