Description

NativeAOT tracing tests in src/tests/tracing/userevents/* crash with ArgumentNullException in ResolveRecordTracePath because Assembly.Location returns empty string in NativeAOT builds. Additionally, NativeAOT has a different directory layout with executables placed in a native/ subdirectory, and NativeAOT tests run executables directly without using corerun.

This PR fixes the tests to work with both CoreCLR and NativeAOT by implementing runtime detection and using conditional logic for path resolution and tracee execution. It reverts PR #123541 which had marked these tests as NativeAOT incompatible.

Changes Made

• Runtime Detection: Detect NativeAOT by checking if Assembly.Location (passed as traceeAssemblyPath) returns empty string
• Conditional Path Resolution:
  • CoreCLR: Use Path.GetDirectoryName(traceeAssemblyPath) to get scenario directory (.../scenario/scenario/)
  • NativeAOT: Use AppContext.BaseDirectory which points to the scenario directory with native/ subdirectory (.../scenario/scenario/native/)
• Directory-Aware Path Resolution:
  • Updated ResolveRecordTracePath to accept isNativeAot parameter and navigate up 3 levels for NativeAOT (from native/ subdirectory) vs 2 levels for CoreCLR
  • Added ResolveScriptFilePath helper method that navigates up 1 level for NativeAOT to find script in parent directory, while CoreCLR finds it in current directory
• Simplified Tracee Execution:
  • Use Environment.ProcessPath for both CoreCLR and NativeAOT (returns corerun for CoreCLR, native executable for NativeAOT)
  • CoreCLR: Arguments are <assembly-path> tracee
  • NativeAOT: Arguments are tracee only
• Null Safety: Added proper null checks for all path operations with meaningful error messages
• Revert PR Mark new userevents tests as native AOT incompatible #123541: Deleted Directory.Build.props that marked tests as NativeAotIncompatible
• Preserved Original API: Kept traceeAssemblyPath parameter so test files remain unchanged

Technical Notes

The solution detects the runtime by checking if traceeAssemblyPath is empty:

• CoreCLR: Assembly.Location returns valid path, traceeAssemblyPath is populated
• NativeAOT: Assembly.Location returns empty string, traceeAssemblyPath is empty

Path resolution handles different directory structures:

• CoreCLR: userEventsScenarioDir is .../tracing/userevents/<scenario>/<scenario>/ (derived from Path.GetDirectoryName() of assembly location)
• NativeAOT: userEventsScenarioDir is .../tracing/userevents/<scenario>/<scenario>/native/ (from AppContext.BaseDirectory)

Record-trace executable resolution:

• CoreCLR: Navigate up 2 levels to reach userevents root
• NativeAOT: Navigate up 3 levels from native/ subdirectory to reach userevents root
• Both resolve to: .../tracing/userevents/common/userevents_common/record-trace

Script file resolution:

• CoreCLR: Script is in current directory (.../scenario/scenario/<scenario>.script)
• NativeAOT: Navigate up 1 level from native/ subdirectory to find script (.../scenario/scenario/<scenario>.script)

Tracee execution uses Environment.ProcessPath for both runtimes:

• CoreCLR tests: Environment.ProcessPath returns corerun path, runs corerun <path-to-scenario.dll> tracee
• NativeAOT tests: Environment.ProcessPath returns native executable path, runs <native-executable> tracee

All test files continue to pass Assembly.Location unchanged, which triggers the correct conditional logic based on the runtime.

TMPDIR is already configured correctly, but diagnostic port discovery will still fail for NativeAOT due to the perfmap dependency (see microsoft/one-collect#226).

// Before: only worked with CoreCLR
string userEventsScenarioDir = Path.GetDirectoryName(traceeAssemblyPath);
string recordTracePath = ResolveRecordTracePath(userEventsScenarioDir);
string scriptFilePath = Path.Combine(userEventsScenarioDir, $"{scenarioName}.script");
traceeStartInfo.FileName = Process.GetCurrentProcess().MainModule!.FileName;
traceeStartInfo.Arguments = $"{traceeAssemblyPath} tracee";

// After: works with both CoreCLR and NativeAOT
bool isNativeAot = string.IsNullOrEmpty(traceeAssemblyPath);
string userEventsScenarioDir = isNativeAot 
    ? AppContext.BaseDirectory 
    : Path.GetDirectoryName(traceeAssemblyPath);

// Path resolution handles different directory depths
string recordTracePath = ResolveRecordTracePath(userEventsScenarioDir, isNativeAot);
string scriptFilePath = ResolveScriptFilePath(userEventsScenarioDir, scenarioName, isNativeAot);

// Simplified to use Environment.ProcessPath for both flavors
traceeStartInfo.FileName = Environment.ProcessPath 
    ?? throw new InvalidOperationException("Environment.ProcessPath is null");
traceeStartInfo.Arguments = isNativeAot 
    ? "tracee" 
    : $"{traceeAssemblyPath} tracee";

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