Update _build/ParallelTestExecution.ps1

Co-authored-by: Matt Lacey <matt@mrlacey.co.uk>

_build/ParallelTestExecution.ps1

@@ -21,7 +21,7 @@ workflow pbatch {
 
     foreach -parallel ($trait in $traits) {
         $outData = InlineScript {
-            . $Using:testrunner $Using:testLibrary -xml "$Using:outputDir\TEST-$Using:trait-Result.xml" -parallel all -trait $Using:trait 
+            . $Using:testrunner $Using:testLibrary -xml "$Using:outputDir\TEST-$Using:trait-Result.xml" -parallel none -trait $Using:trait 
         } -AppendOutput $true -MergeErrorToOutput $false
      
         Write-output "Trait $trait execution:" $outData "" ""