[TD] Emit metrics to compare heuristic quality (#108192)
When a test fails, we will now emit fine grained details about how accurately heuristics predicted the relevance of that test.
## Context
Why only look at failing tests? Our only signal that a PR is most likely relevant to a test is whether or not a test fails on it. Green tests don't tell us if the success was due to the code being good vs being irrelevant. This isn't a perfect measure, since it can miscategorize unstable and flaky failures as having been "missed" by the heuristics, but it's a reasonable approximation.
## What's measured?
The metrics this PR collects are designed to answer the following questions
### How comprehensive are the heuristics?
- What's the false negative rate, the % of failures that ideally should have been prioritized but weren't? (Both at an aggregate level and at a per heuristic level)
### How precise are the heuristics?
- What % of failed tests were prioritized by a given heuristic? What % was prioritized overall?
- How relevant was a failed test was considered to be? (Both a aggregate level and at a per heuristic level)
- What % of time was a given heuristic prioritizing a failing test higher than any other heuristic?
Pull Request resolved: https://github.com/pytorch/pytorch/pull/108192
Approved by: https://github.com/huydhn
ghstack dependencies: #108117
