(temporarily?) add RunTestsInLoop.ps1

tests/ImageSharp.Tests/RunTestsInLoop.ps1

@@ -0,0 +1,21 @@
+# This script can be used to collect logs from sporadic bugs
+Param(
+    [int]$TestRunCount=10,
+    [string]$TargetFramework="netcoreapp3.1"
+)
+
+$runId = Get-Random -Minimum 0 -Maximum 9999
+
+dotnet build -c Release -f $TargetFramework
+for ($i = 0; $i -lt $TestRunCount; $i++) {
+    $logFile = ".\_testlog-" + $runId.ToString("d4") + "-run-" + $i.ToString("d3") + ".log"
+    Write-Host "Test run $i ..."
+    & dotnet test --no-build -c Release -f $TargetFramework 3>&1 2>&1 > $logFile
+    if ($LastExitCode -eq 0) {
+        Write-Host "Success!"
+        Remove-Item $logFile
+    }
+    else {
+        Write-Host "Failed: $logFile"
+    }
+}