CI: Attempt to fix Windows by setting SystemRoot env variable

Author: amotl

src/crate/testing/layer.py

@@ -224,6 +224,7 @@ def __init__(self,
         self.env.setdefault('CRATE_USE_IPV4', 'true')
         if sys.platform == 'win32':
             self.env.setdefault('_JAVA_OPTIONS', '-Djava.awt.headless=true -Djava.net.preferIPv4Stack=true')
+            self.env.setdefault('SystemRoot', 'C:\\Windows')
         self.env.setdefault('JAVA_HOME', os.environ.get('JAVA_HOME', ''))
         self._stdout_consumers = []
         self.conn_pool = urllib3.PoolManager(num_pools=1)