Rollup merge of #61632 - alexcrichton:azure-pipelines-cpu, r=pietroalbini

Rollup merge of #61632 - alexcrichton:azure-pipelines-cpu, r=pietroalbini

ci: Collect CPU usage statistics on Azure

This commit adds a script which we'll execute on Azure Pipelines which
is intended to run in the background and passively collect CPU usage
statistics for our builders. The intention here is that we can use this
information over time to diagnose issues with builders, see where we can
optimize our build, fix parallelism issues, etc. This might not end up
being too useful in the long run but it's data we've wanted to collect
for quite some time now, so here's a stab at it!

Comments about how this is intended to work can be found in the python
script used here to collect CPU usage statistics.

Closes #48828