Add R2R Composite Single File benchmark modes

[Copilot]

Adds crossgen2 composite ReadyToRun benchmark variants to the Single File scenarios.

Changes

• Two new modes in build/singlefile-scenarios.yml:

  • R2RComposite-Windows: win-x64 RID, Windows-gated
  • R2RComposite-Linux: linux-x64 RID, Linux-gated

• Build properties: PublishReadyToRun=true, PublishReadyToRunComposite=true, PublishSingleFile=true, RuntimeIdentifier=<rid>

• Crank properties: mode=R2RComposite, rid=<rid>

• OS gating: --application.options.requiredOperatingSystem <windows|linux>

Impact

Adds 4 new benchmark configurations (Json Platform + Plaintext × 2 RIDs) to the existing pipeline matrix. Existing modes unchanged.

Note: Does not set PublishReadyToRunUseCrossgen2=true explicitly—relies on modern SDK defaults.

Original prompt

Add new Single File benchmark modes for crossgen2 composite ReadyToRun publish.

Background:
The Single File benchmarks are scheduled via the Azure Pipelines template build/singlefile-scenarios.yml, which defines a list of scenarios and modes and then cross-products them when publishing crank jobs.

Goal:
Add a scenario variant (implemented as two new modes) corresponding to running dotnet publish with:

• -c Release
• -r <RID>
• -p:PublishReadyToRun=true
• -p:PublishReadyToRunComposite=true

Because the RID is OS-specific, implement Option A:

• Add two new modes:
  • Windows: RID win-x64, gated with --application.options.requiredOperatingSystem windows
  • Linux: RID linux-x64, gated with --application.options.requiredOperatingSystem linux

Important constraints:

• Limit to PublishReadyToRun=true (do not explicitly set PublishReadyToRunUseCrossgen2=true). Rely on modern SDK defaults implying crossgen2.
• Use buildArguments MSBuild properties to pass the RID via /p:RuntimeIdentifier=<rid> (equivalent to dotnet publish -r <rid> in this template style).
• Ensure these new modes apply to both existing Single File scenarios (Json Platform and Plaintext) automatically via the existing nested iteration.
• Add optional --property rid=<rid> and set --property mode=R2RComposite (or similar) consistent with existing template properties.

Files to change:

• build/singlefile-scenarios.yml

Acceptance criteria:

• The YAML remains valid.
• Two new modes appear in the published tasks matrix (Windows and Linux) and are OS-gated.
• Existing modes and behavior remain unchanged.

This pull request was created from Copilot chat.

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