add samplecategorical

[enkilee]

Add SampleCategorical function
Function: Randomly sample an integer according to the given distribution.
param1(vector): candidates Candidate set of integers.
param2(vector): probs Probability distribution of candidate integer set.
Return Value(int): Random variables sampled.

• 【2022】CINN开发任务跟踪 #1115
• 原始 PR：Add_SimpleCategorical #1169

[luotao1]

@enkilee 请解决下流水线失败的问题

[enkilee]

@luotao1
ci已都过

[CtfGo]

  Expr SampleCategorical(const std::vector<int>& candidates, const std::vector<float>& probs, const std::vector<int>& decision = {});

参考SamplePerfectTile，增加decision参数可，选值为空或仅包含1个元素，表示先前的sample结果，若decision不为空，则直接以该值作为此次sample结果，以便后续schedule_desc replay时能复现schedule过程。

[CtfGo]

  CheckTracingOutputs(result, trace);
  CheckTracingOutputs(result, ir_sch.GetTraceDesc());
  CheckReplayResult(ir_sch, trace);
  CheckReplayResult(ir_sch, ir_sch.GetTraceDesc());

单测增加校验输出

[enkilee]

@CtfGo ci都已过

[CtfGo]

LGTM