[mono][tests] Parallel AOT compilation of runtime tests on iOS platforms (#86089)

[mono][tests] Parallel AOT compilation of runtime tests on iOS platforms  (#86089)

The Helix payload is generated using the runtime pipeline. Then, the libraries pipeline is utilized to AOT compile and execute the tests on Helix. The build-runtime-tests-and-send-to-helix.yml is updated with the compileOnHelix parameter, which if set, uses the libraries/helix.yml template instead of the runtime send-to-helix-step.yml template. The runtime and libraries pipelines are updated to support AOT compilation of runtime tests on Helix.