Add Arm64 PGO Builds

[davidwrighton]

• Add PGO for arm64
• Switch to using compiler container images which support PGO compilation on Arm64

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Issue Details

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• Add PGO for arm64

• This initial PR is not to be checked in as it adds the PGO to the PR build, which isn't needed long term, but I need to test it before merging the official build change.

Author:	davidwrighton
Assignees:	davidwrighton
Labels:	area-Infrastructure-libraries
Milestone:	-

[deeprobin]

I guess this will just fail due to an infrastructure problem https://github.com/dotnet/core-eng/issues/15812.

[ghost]

This pull request has been automatically marked no-recent-activity because it has not had any activity for 14 days. It will be closed if no further activity occurs within 14 more days. Any new comment (by anyone, not necessarily the author) will remove no-recent-activity.

[ghost]

This pull request will now be closed since it had been marked no-recent-activity but received no further activity in the past 14 days. It is still possible to reopen or comment on the pull request, but please note that it will be locked if it remains inactive for another 30 days.

[davidwrighton]

The underlying problems with Linux arm64 compilation have been fixed, re-opening the PR.

[davidwrighton]

@hoyosjs is there any way to have confidence this won't bork the official build? I've had the changes run in a PR job, and that passed, but I've now removed that logic (as we don't want PGO compilation to happen in PR).

[hoyosjs]

This is an official build of it: https://dev.azure.com/dnceng/internal/_build/results?buildId=1763698&view=results

[hoyosjs]

The internal job LGTM WRT to the PGO changes.