jdk11_headless: fix the build on amd64

This fixes:

checking user specified JVM feature list...
configure: error: Cannot continue
configure: Unknown JVM features specified: "zgc--enable-headless-only"
configure: The available JVM features are: "aot cds cmsgc compiler1 compiler2 dtrace epsilongc g1gc graal jfr jni-check jvmci jvmti link-time-opt management minimal nmt parallelgc serialgc services static-build vm-structs zero zgc"
configure exiting with result code 1
builder for '/nix/store/1awwzd98crcgxad3srdkv8smhxgiz2qp-openjdk-11.0.1-b13.drv' failed with exit code 1