[tests] Fail fast when the emulator package manager service is wedged

[simonrozsival]

Problem

Device integration tests (DeviceTest) gate on adb shell echo OK in the shared [SetUp] before running. That check succeeds even when the emulator's system_server / package manager service has crashed or wedged. As a result the health check passes, the test proceeds to build and install an app, and then fails deep inside the build with a cryptic error:

[BT:1.18.3] error: Unexpected output of 'pm list features' command:
    'cmd: Failure calling service package: Broken pipe (32)'
error XABAS0000: com.android.tools.build.bundletool...AdbOutputParseException
   at ...DeviceFeaturesParser.parse
   at ...DeviceAnalyzer.getDeviceSpec

Because these tests run a combined /t:Build,Install target, an emulator/service failure surfaces as a misleading FailedBuildException: "Build failure" — reported as N unrelated per-test failures long after the emulator actually died, instead of a single clear "emulator unusable" signal up front.

Observed in the wild: a single macOS emulator lane failed 8 diverse tests (BundleTool, Debugging, InstallAndRun, StoreKey) while every other build/test lane stayed green — the classic signature of a wedged package service, not a product regression.

Fix

Probe the package manager service — the same pm list features binder path that bundletool build-apks --connected-device and adb install rely on — in the shared SetUp:

• IsPackageManagerResponsive(out diagnostic) — retries a few times so a momentary hiccup doesn't trigger an unnecessary emulator restart.
• AssertPackageManagerResponsive() — if the service is wedged, restart the emulator once; if it's still broken, Assert.Inconclusive with a clear "package manager service is unresponsive (system_server likely crashed)" message.

This surfaces the failure before building/installing the app, once, with a real reason — and marks it inconclusive (an infrastructure problem) rather than turning an emulator crash into product-test failures, consistent with the existing RestartDevice transient-failure handling.

[Copilot]

Pull request overview

Adds a stronger emulator health check to the shared device-test SetUp so infrastructure failures (wedged system_server / package manager binder) are detected early and reported as inconclusive rather than cascading into many misleading build/install test failures.

Changes:

• Introduces IsPackageManagerResponsive(out diagnostic) which probes adb shell pm list features with retries to detect a broken package service.
• Adds AssertPackageManagerResponsive() to restart the emulator once and mark the run inconclusive if the service remains unresponsive.
• Calls the new assertion from the shared [SetUp] to fail fast before build/install work begins.

Show a summary per file

File	Description
src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/Utilities/DeviceTest.cs	Adds package-manager responsiveness probing and a fail-fast setup check to restart/skip on emulator service wedges.

Copilot's findings

• Files reviewed: 1/1 changed files
• Comments generated: 2