Use JDK 21 for agents of Alpine controller

Author: MarkEWaite

docker_run.py

@@ -85,6 +85,8 @@ def get_windows_dir():
 def get_jagent_java_home():
     if "jdk21" in docker_build.get_current_branch():
         return "/home/jagent/tools/jdk-21.0.7+6"
+    if "alpine" in docker_build.get_current_branch():
+        return "/home/jagent/tools/jdk-21.0.7+6"
     if "weekly" in docker_build.get_current_branch():
         return "/home/jagent/tools/jdk-21.0.7+6"
     return "/home/jagent/tools/jdk-17.0.15+6"