Enhance to fill the last delay slot of a call with an
unconditional jump.
(fill_simple_delay_slots): Look for the case of a call/branch
first. If this applies, record the jump as `last_delay_insn'.
Later, don't look for additional delay insns if the last one has
alreay been filled.
(mark_target_live_regs): A sequence may end in an unconditional
branch.
From-SVN: r1969