RFR: Usage tracking cleanup [v6]

[William Kemper]

> There are many nuances to tracing memory utilization. Shenandoah track's usage, waste by humongous objects, padding for promotion LABs alignment and all this is also tracked by generation, the heap and feeds into the heuristics and the pacer. The code to update all of these values and route them to the right places was spread across the allocation call stack. This change consolidates all of the logic into one method, invoked near the end of the allocation.

William Kemper has updated the pull request incrementally with one additional commit since the last revision:

  Fix typo

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Changes:
  - all: https://git.openjdk.org/shenandoah/pull/260/files
  - new: https://git.openjdk.org/shenandoah/pull/260/files/31003e80..ca1e79f6

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=shenandoah&pr=260&range=05
 - incr: https://webrevs.openjdk.org/?repo=shenandoah&pr=260&range=04-05

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/shenandoah/pull/260.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah.git pull/260/head:pull/260

PR: https://git.openjdk.org/shenandoah/pull/260