To keep track of memory characteristics of a JS program use
GetHeapSpaceStatistics from a combination of
- a GC epilogue callback registered using AddGCEpilogueCallback
- an interrupt registered using RequestInterrupt

Rationale:
The feature is currently broken as those callbacks are (also) executed from
background threads, breaking our implicit contract for only performing callbacks
on the foreground thread. Furhtermore, it's not clear for the embedder whether
these allocations originate in JS, or are required for a GC.

Note:
- The already deprecated non-isolate versions are removed with this CL.

R=jochen@chromium.org
BUG=v8:4813
LOG=Y

Review URL: https://codereview.chromium.org/1886573006

Cr-Commit-Position: refs/heads/master@{#35474}