vmm_tests_run: selections and deps improvements

[tjones60]

Makes the following improvements to xflowey vmm_tests_run:

• Set the correct registry key for hardware isolation.
• Indicate that a restart is required when installing test deps.
• Check whether registry keys are set and hyper-v is installed even when running without --install-missing-deps in a way that doesn't require admin.
• Always add all dep install commands to install_deps.ps1 in case the output (when running without --build-only; this was already the case when the tests were not run locally) is copied to another machine later without the deps installed on the machine that built and ran the tests originally.
• Correctly detect whether a test filter requires hyperv-v and hardware isolation.
• Add option for disabling secure avic and move the feature configuration to build_openhcl_igvm_from_recipe.
• Only build the necessary OpenHCL recipes, rather than all or nothing.

[Copilot]

Pull request overview

This PR improves the local xflowey vmm-tests-run pipeline by refining dependency installation/verification on Windows, improving artifact/build selection so only necessary OpenHCL recipes are built, and adding a --disable-secure-avic option that flows into IGVM generation.

Changes:

• Refactors Windows test dependency installation to better handle registry keys/feature checks and to surface “restart required” after changes.
• Improves artifact resolution/build selection so only the required OpenHCL IGVM recipes are built (standard/dev/cvm/linux-direct).
• Adds --disable-secure-avic to vmm-tests-run and plumbs it through OpenHCL IGVM building.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
support/powershell_builder/src/lib.rs	Makes the PowerShell builder crate compile outside cfg(windows) (needed for WSL/Linux-host flowey compilation).
support/powershell_builder/Cargo.toml	Makes dependencies unconditional (no longer Windows-target-only).
flowey/flowey_lib_hvlite/src/install_vmm_tests_deps.rs	Refactors Windows dependency install/check logic; adds restart-required signaling; updates registry key handling including correct hardware isolation path.
flowey/flowey_lib_hvlite/src/build_openhcl_igvm_from_recipe.rs	Moves disable_secure_avic feature configuration into the recipe build path.
flowey/flowey_lib_hvlite/src/_jobs/local_build_igvm.rs	Removes duplicate disable_secure_avic feature insertion (now handled centrally in recipe build).
flowey/flowey_lib_hvlite/src/_jobs/local_build_and_run_nextest_vmm_tests.rs	Splits OpenHCL build selections by recipe type and builds only what’s needed; plumbs disable_secure_avic.
flowey/flowey_lib_hvlite/Cargo.toml	Makes powershell_builder an unconditional dependency (needed because it’s referenced from non-cfg(windows) code paths).
flowey/flowey_hvlite/src/pipelines/vmm_tests_run.rs	Adds --disable-secure-avic, improves selection logging, and improves hyperv/hardware-isolation detection from selected tests.