Capture memory monitor report before OOM crash

[stephanos]

What changed?

Follow-up to #9027

1. Print memory stats to both file and stdout (new!)
2. Print Go heap report once a memory threshold is reached (ie close to OOM kill)
3. Add alloc_objects to Go heap report

See example:

(note that Go test output is buffered so they all appear mostly sequentially)

Why?

Gain ability to capture memory usage and Go heap report before an OOM kill.

How did you test it?

• built
• run locally and tested manually
• covered by existing tests
• added new unit test(s)
• added new functional test(s)