Summary:
In crash test, when coming to each kill point, we start a random class using seed as current second. With this approach, for every second, the random number used is the same. However, in each second, there are multiple kill points with different frequency. It makes it hard to reason about chance of kill point to trigger. With this commit, we use thread local random seed to generate the random number, so that it will take different values per second, hoping it makes chances of killing much easier to reason about.
Also significantly reduce the kill odd to make sure time before kiling is similar as before.
Test Plan: Run white box crash test and see the killing happens as expected and the run time time before killing reasonable.
Reviewers: kradhakrishnan, IslamAbdelRahman, rven, yhchiang, andrewkr, anthony
Reviewed By: anthony
Subscribers: leveldb, dhruba
Differential Revision: https://reviews.facebook.net/D52971
fdbff42391