Memory size: better alignment of dart memory tools with native memory tools

[polina-c]

Numbers in DevTools > Memory should match numbers in native tools.

Different tools show different total memory consumption numbers, not apple to apple or not sync or not precise: mac usage monitor, DevTools > Memory > diff (total heap, reachable heap), DevTools > Memory > profile, DevTools > Memory > chart, in-process ProcessInfo.rss.

[polina-c]

• [ ] Enable visibility for totals
  • [ ] request for vm team: https://github.com/dart-lang/sdk/issues/53135
  • [ ] Dart heap and reachable size: https://github.com/flutter/devtools/pull/5593/
  • [ ] Show getProcessMemoryUsage
  • [ ] Total native
• [ ] Enable break down for native memory size

[kenzieschmoll]

A comment from the DevTools survey related to accuracy of size and instances: "Seems like some Instances are not listed, sometimes total mem size does not adds up"