Try to make windows test script less likely to hang

Author: plemarquand

scripts/test_windows.ps1

@@ -64,10 +64,10 @@ npm ci -ignore-script node-pty
 npm run lint
 npm run format
 npm run package
-$Process = Start-Process npm "run integration-test" -Wait -PassThru -NoNewWindow
-if ($Process.ExitCode -eq 0) {
+npm run integration-test
+if ($LASTEXITCODE -eq 0) {
     Write-Host 'SUCCESS'
 } else {
-    Write-Host  ('FAILED ({0})' -f $Process.ExitCode)
+    Write-Host ('FAILED ({0})' -f $LASTEXITCODE)
     exit 1
 }