(pa_insn_adjust_length): Rework.  Add code to handle
millicode calls with unfilled delay slots and inline block moves.

(compute_movstrsi_length): New function to compute the length of
a movstrsi pattern.

(output_cbranch): Long branches with unfilled delay slots can
always nullify the following instruction if their delay slot
was not filled.

From-SVN: r4602