[Broadcast]Fix empty broadcast

[AndPuQing]

PR types

Bug fixes

PR changes

APIs

Describe

该 PR 修复了空张量 broadcast 时产生的非预期输出。例如：

# before
>>> import paddle
>>> print(paddle.broadcast_shape([0], [0, 1]))
[-1, -1]

# after
>>> import paddle
>>> print(paddle.broadcast_shape([0], [0, 1]))
[0, 0]

在结果上与numpy的结果保持一致

Relevant

#49925 Case7: paddle.distribution.StickBreakingTransform

#49927

[paddle-bot]

你的PR提交成功，感谢你对开源项目的贡献!
请关注后续CI自动化测试结果，详情请参考Paddle-CI手册。
Your PR has been submitted. Thanks for your contribution!
Please wait for the result of CI firstly. See Paddle CI Manual for details.

[luotao1]

在 develop 上已经无法复现