feat(test): Add timing measurement for integration tests (#985)

[xingzihai]

This PR implements timing measurement for integration tests as requested in Issue #985.

Summary

Currently, the integration test suite on Windows periodically takes longer than 10 minutes, which is quite long. This PR adds timing measurement infrastructure to help identify which stages are taking the most time.

Changes

TimingHelper.cs (new file)

• TestTimingResult: Record to store timing data for each test execution
• TestTimingCollector: Static class to collect and aggregate timing results, save to JSON
• TestTimer: Helper class for measuring execution time

IntegrationTestContext.cs (modified)

• Added TimingOutputDirectory property
• Initialize timing collector in InitializeOnce()
• Save timing results to JSON in DisposeAsync()

IntegrationTestRunner.cs (modified)

• Added TestExecutionResult record to capture timing data
• Modified CompileAndRunWithNative() and CompileAndRunWithCesium() to return timing data
• Modified DoTest() to:
  • Capture timing data from compilation methods
  • Create TestTimingResult with full timing breakdown
  • Record results to TestTimingCollector

Features

✅ Measures timing for:

• Native compile time (MSVC on Windows, GCC on Linux/macOS)
• Cesium compile time
• Native execution time
• Cesium execution time
• Total test time

✅ Records metadata:

• Test name, target framework, target arch
• Source files, operating system
• Success/failure status and error messages

✅ Outputs to JSON:

• Path: artifacts/timing/integration_test_timing_TIMESTAMP.json
• Includes summary statistics (average times, pass/fail counts)
• Downloadable from CI artifacts

✅ Cross-platform:

• Works on Windows, Linux, macOS

Testing

The code has been implemented following the existing patterns in the codebase. Tests will run automatically via CI.

Related Issue

Closes #985

[ForNeVeR]

You seems to have opened two PRs addressing the same topic (the other one being #986); let's please focus on one of them? I'll leave the first one open, and will close this one.