html4 flag does not work with OpenJDK 14

[externl]

> Task :freeze-compat:javadoc
Task ':freeze-compat:javadoc' is not up-to-date because:
  No history is available.
Starting process 'command '/Library/Java/JavaVirtualMachines/openjdk-14.0.1.jdk/Contents/Home/bin/javadoc''. Working directory: /Users/vagrant/workspace/freeze-dist/3.7/dist-utils/build/freeze/builds/freeze-demos-clang-x64-default/java/src/Freeze Command: /Library/Java/JavaVirtualMachines/openjdk-14.0.1.jdk/Contents/Home/bin/javadoc @/Users/vagrant/workspace/freeze-dist/3.7/dist-utils/build/freeze/builds/freeze-demos-clang-x64-default/java/src/Freeze/build/tmp/javadoc/javadoc.options
Successfully started process 'command '/Library/Java/JavaVirtualMachines/openjdk-14.0.1.jdk/Contents/Home/bin/javadoc''
javadoc: error - invalid flag: -html4
Usage:
    javadoc [options] [packagenames] [sourcefiles] [@files]

We have

if(JavaVersion.current() > JavaVersion.VERSION_1_8) {
        // Add -quiet to workaround Gradle bug https://github.com/gradle/gradle/issues/2354
        options.addStringOption("html4", "-quiet")
 }

We should probably just remove this.