Blocked revisions 70071 via svnmerge

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  r70071 | jeffrey.yasskin | 2009-02-28 11:03:21 -0800 (Sat, 28 Feb 2009) | 5 lines

  Backport r69961 to trunk, replacing JUMP_IF_{TRUE,FALSE} with
  POP_JUMP_IF_{TRUE,FALSE} and JUMP_IF_{TRUE,FALSE}_OR_POP. This avoids executing
  a POP_TOP on each conditional and sometimes allows the peephole optimizer to
  skip a JUMP_ABSOLUTE entirely. It speeds up list comprehensions significantly.
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