dwarf2out: Convert regs_saved_in_regs to VEC.

dwarf2out: Convert regs_saved_in_regs to VEC.

        * dwarf2out.c (struct reg_saved_in_data): Provide a typedef.
        Define a vector of this type.
        (regs_saved_in_regs): Use a VEC.
        (num_regs_saved_in_regs): Remove.
        (compare_reg_or_pc): New.
        (record_reg_saved_in_reg): Split out from...
        (dwarf2out_flush_queued_reg_saves): ... here.
        (clobbers_queued_reg_save): Update for VEC.
        (reg_saved_in): Likewise.
        (dwarf2out_frame_debug_init): Likewise.
        (dwarf2out_reg_save_reg): Use record_reg_saved_in_reg.
        (dwarf2out_frame_debug_cfa_register): Likewise.

From-SVN: r175727