Add a test for the powershell hang fix (PowerShell#5451)

- Add test for the powershell hang fix
- Ignore the 'Sync-PSTags' warning

build.psm1

@@ -568,7 +568,7 @@ Fix steps:
         if ($ReleaseTagToUse) {
             $ReleaseVersion = $ReleaseTagToUse
         } else {
-            $ReleaseVersion = (Get-PSCommitId) -replace '^v'
+            $ReleaseVersion = (Get-PSCommitId -WarningAction SilentlyContinue) -replace '^v'
         }
 
         Start-NativeExecution { & "~/.rcedit/rcedit-x64.exe" "$($Options.Output)" --set-icon "$PSScriptRoot\assets\Powershell_black.ico" `

test/powershell/engine/Api/BasicEngine.Tests.ps1

@@ -21,3 +21,27 @@ Describe 'Basic engine APIs' -Tags "CI" {
         }
     }
 }
+
+Describe "Clean up open Runspaces when exit powershell process" -Tags "Feature" {
+    It "PowerShell process should not freeze at exit" {
+        $command = @'
+-c $rs = [runspacefactory]::CreateRunspacePool(1,5)
+$rs.Open()
+$ps = [powershell]::Create()
+$ps.RunspacePool = $rs
+$null = $ps.AddScript(1).Invoke()
+write-host should_not_hang_at_exit
+exit
+'@
+        $process = Start-Process pwsh -ArgumentList $command -PassThru
+        Wait-UntilTrue -sb { $process.HasExited } -TimeoutInMilliseconds 5000 -IntervalInMilliseconds 1000 > $null
+
+        $expect = "powershell process exits in 5 seconds"
+        if (-not $process.HasExited) {
+            Stop-Process -InputObject $process -Force -ErrorAction SilentlyContinue
+            "powershell process doesn't exit in 5 seconds" | Should Be $expect
+        } else {
+            $expect | Should Be $expect
+        }
+    }
+}