Add WSL marker

Change-Id: Ia33add2cca639e91167f4dd2dab77f790e2c46b9
Reviewed-on: https://chromium-review.googlesource.com/c/external/github.com/WebKit/JetStream/+/6422138
Reviewed-by: Marja Hölttä <[email protected]>
Reviewed-by: Leszek Swirski <[email protected]>
1 file changed