Integration tests fail on Windows

[costin]

The latest master cannot run integration tests on windows due to:

Exception in thread "main" java.nio.file.AccessDeniedException: C:\Windows\elasticsearch
	at sun.nio.fs.WindowsException.translateToIOException(WindowsException.java:83)
	at sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:97)
	at sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:102)
	at sun.nio.fs.WindowsFileSystemProvider.createDirectory(WindowsFileSystemProvider.java:504)
	at java.nio.file.Files.createDirectory(Files.java:674)
	at java.nio.file.Files.createAndCheckIsDirectory(Files.java:781)
	at java.nio.file.Files.createDirectories(Files.java:767)
	at org.elasticsearch.tools.launchers.TempDirectory.main(TempDirectory.java:52)

It looks like the temporary folder is not set which causes the default/system folder (C:\Windows) to be used instead which obviously fails.

From try-outs it looks commit 465343f introduced this change in behavior.

[elasticmachine]

Pinging @elastic/es-core-infra

[alpar-t]

I managed to reproduce this on a Win2012r2 image we use for packaging tests in CI.
using gradlew -p x-pack/plugin/sql/qa/single-node check without setting runtime java. I do have TMP set. Running the run.bat wrapper script doesn't reproduces the problem, which leads me to believe the problem is that env vars do not get sent when this is called.
This reproduces with RUNTIME_JAVA_HOME set as well

[alpar-t]

I can confirm that the env is not inherited by the wrapper script:

COMSPEC=C:\Windows\SYSTEM32\cmd.exe
ES_JAVA_OPTS=-Xms512m -Xmx512m  -ea -esa
ES_PATH_CONF=C:\ELASTI~1\x-pack\plugin\sql\qa\single-node\build\cluster\integTestCluster node0\elasticsearch-8.0.0-SNAPSHOT\config
PATHEXT=.COM;.EXE;.BAT;.CMD;.VBS;.JS;.WS;.MSC
PROMPT=$P$G
SystemRoot=C:\Windows