build/ci: Remove JDK from builder image

The JDK is not used and pulls in further unnecessary dependencies.

Change-Id: I46223497d6809b911ab200bd255c20054e7c78d2
Reviewed-on: https://review.monogon.dev/c/monogon/+/413
Vouch-Run-CI: Leopold Schabel <leo@nexantic.com>
Reviewed-by: Leopold Schabel <leo@nexantic.com>
diff --git a/build/ci/Dockerfile b/build/ci/Dockerfile
index 8cf7146..5f5895c 100644
--- a/build/ci/Dockerfile
+++ b/build/ci/Dockerfile
@@ -30,8 +30,7 @@
 	grpc-cli \
 	nc \
 	python-unversioned-command \
-	openssl-devel \
-	java-11-openjdk
+	openssl-devel
 
 # Create CI build user. This is not used by scripts/bin/bazel, but instead only
 # used by CI infrastructure to run build agents as.