Re-enable IdenticalSubmissionsShouldCompleteAndNotHangTheBuildOnMissi…

…ngTargetExceptions (#9253)

Fixes #9245

Context
The test was disabled to unblock PR CI.

Changes Made
Increased the relevant timeout.

Testing
The test is reliably passing now.

Notes
This turned out to be an issue with the sleep command we use on Windows. In some cases PowerShell can take a super long time to start. I have been able to reproduce locally by enabling Fusion logging. Thread times of the powershell process:

image

We spend almost 10 seconds just loading assemblies, so the timeout of 10 seconds for the entire build was not enough.

I don't have a full understanding of the mechanism that slows down PowerShell this much. At this point I'm happy we were able to confirm it's not a product issue, although I'm wondering if there is a better and more light-weight sleep command we could use on Windows instead (e.g. ping 127.0.0.1 -n <seconds>). Reviewers please opine.

EDIT: In my trace, file system operations block extensively with wdfilter.sys on the stack, so the likely explanation for the issue appearing all of a sudden is a Defender update.

src/Build.UnitTests/BackEnd/BuildManager_Tests.cs

@@ -4046,7 +4046,7 @@ public void MultiProcReentrantProjectWithCallTargetDoesNotFail()
             }
         }
 
-        [Fact(Skip = "https://github.com/dotnet/msbuild/issues/9245")]
+        [Fact]
         public void IdenticalSubmissionsShouldCompleteAndNotHangTheBuildOnMissingTargetExceptions()
         {
             var projectContents =
@@ -4114,8 +4114,8 @@ handoff logging completion to the BuildManager.
                     submission1.ExecuteAsync(null, null);
                     submission2.ExecuteAsync(null, null);
 
-                    submission1.WaitHandle.WaitOne(TimeSpan.FromSeconds(10));
-                    submission2.WaitHandle.WaitOne(TimeSpan.FromSeconds(10));
+                    submission1.WaitHandle.WaitOne(TimeSpan.FromSeconds(20));
+                    submission2.WaitHandle.WaitOne(TimeSpan.FromSeconds(20));
 
                     submission1.IsCompleted.ShouldBeTrue();
                     submission2.IsCompleted.ShouldBeTrue();