Implement AllToAll collective op

[shaahji]

Description

Implement AllToAll collective op

Motivation and Context

Follow up to/continuation of #14399

[shaahji]

Do I need to do something for the Linux pipelines to kick in? The Linux pipeline aren't queued and won't finish.

[mszhanyi]

/azp run Linux CPU CI Pipeline

[azure-pipelines]

Command 'Linux' is not supported by Azure Pipelines.

Supported commands

• help:
• Get descriptions, examples and documentation about supported commands
• Example: help "command_name"
• list:
• List all pipelines for this repository using a comment.
• Example: "list"
• run:
• Run all pipelines or specific pipelines for this repository using a comment. Use this command by itself to trigger all related pipelines, or specify specific pipelines to run.
• Example: "run" or "run pipeline_name, pipeline_name, pipeline_name"
• where:
• Report back the Azure DevOps orgs that are related to this repository and org
• Example: "where"

See additional documentation.

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[shaahji]

Opened a new PR with the branch from the host repo instead of the forked one. Pipeline runs aren't supported from remote repos preventing merges.