Separate process per test for TS2K Windows tests (#706)

This is workaround memory issues on CI builds for Windows on GitHub Actions

test/builds/multiprocess_ts2k_tests.ps1

@@ -0,0 +1,16 @@
+# The tests run out of memory on CI see https://github.com/microsoft/knossos-ksc/issues/679 for details of the leak in module creation
+# pytest-forked on Windows doesn't help, so: collect the tests, run one at a time, exit on any failure
+$alltests = pytest $PSScriptRoot\..\ts2k\ --collect-only --quiet --disable-pytest-warnings | Select-Object -skip 2 -last 1000000
+
+$alltests
+
+Foreach ($test in $alltests)
+{
+    $test
+    $test_output = pytest $test
+    if ( 0 -ne $LastExitcode)
+    {
+        Write-Output $test_output
+        exit $LastExitcode
+    } 
+}

test/builds/test_pytest_PyTorchPreview.cmd

@@ -34,7 +34,10 @@ python -m pip install --editable . || exit /b
 cd ../..
 
 REM we only run a single test for now, multiple tests run out of heap see #679
-pytest test\ts2k\test_ts2k.py -k test_cat
+REM pytest test\ts2k\test_ts2k.py -k test_cat
 
 REM echo Running pytest on ts2k
 REM pytest test/ts2k || exit /b
+
+REM this runs the tests one by one avoiding the memory issues
+powershell.exe -file "%~dp0multiprocess_ts2k_tests.ps1" || exit /b