Investigate why createdump generated dumps are so large on MacOS

[mikem8361]

We are seeing ~6GB dumps on MacOS in the CI jobs.

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Issue Details

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We are seeing ~6GB dumps on MacOS in the CI jobs.

Author:	mikem8361
Assignees:	mikem8361
Labels:	area-Diagnostics-coreclr
Milestone:	7.0.0

[janvorli]

Just FYI, I am getting large dump sizes (over 3GB at least) even for a trivial C app with main containing only a dereference of NULL and nothing else. So it seems to be a general macOS issue.

[danmoseley]

Much discussion occurred here https://github.com/dotnet/core-eng/issues/15333
Another suggestion was to investigate how compressible these huge dumps are.