8341485: GenShen: Make evac tracker a non-product feature and confine it to generational mode

[earthling-amzn]

During the course of development of the generational mode, we added a feature to keep track of which threads were evacuating objects and how many evacuations lost the race. The instrumentation added unwarranted overhead. This change makes this instrumentation a non-product feature for the generational mode and removes it entirely from the non-generational modes.

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Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• Change must be properly reviewed (1 review required, with at least 1 Committer)

Issue

• JDK-8341485: GenShen: Make evac tracker a non-product feature and confine it to generational mode (Task - P4)

Reviewers

• Kelvin Nilsen (@kdnilsen - Committer)
• Y. Srinivas Ramakrishna (@ysramakrishna - Committer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/shenandoah.git pull/506/head:pull/506
$ git checkout pull/506

Update a local copy of the PR:
$ git checkout pull/506
$ git pull https://git.openjdk.org/shenandoah.git pull/506/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 506

View PR using the GUI difftool:
$ git pr show -t 506

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/shenandoah/pull/506.diff

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[openjdk]

@earthling-amzn This change now passes all automated pre-integration checks.

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8341485: GenShen: Make evac tracker a non-product feature and confine it to generational mode

Reviewed-by: kdnilsen, ysr

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[mlbridge]

Webrevs

• 00: Full (f6d88945)

[ysramakrishna]

Looks good to me.

(Left a comment/question about another change that kinda snuck in; but it's probably OK to sneak it in here rather than the extra overhead of a separate PR, if you intended it...)

[earthling-amzn]

/integrate

[openjdk]

Going to push as commit bd7d34d.

[openjdk]

@earthling-amzn Pushed as commit bd7d34d.

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