Looks like JDK-8304913 broke the ARM32 build. Error during build is:

jdk.tools.jlink.plugin.PluginException: ModuleTarget is malformed: No enum constant jdk.internal.util.Architecture.ARM
at jdk.jlink/jdk.tools.jlink.builder.DefaultImageBuilder.storeFiles(DefaultImageBuilder.java:181)
at jdk.jlink/jdk.tools.jlink.internal.ImagePluginStack.storeFiles(ImagePluginStack.java:486)
at jdk.jlink/jdk.tools.jlink.internal.ImageFileCreator.writeImage(ImageFileCreator.java:168)
at jdk.jlink/jdk.tools.jlink.internal.ImageFileCreator.create(ImageFileCreator.java:100)
at jdk.jlink/jdk.tools.jlink.internal.JlinkTask$ImageHelper.retrieve(JlinkTask.java:860)
at jdk.jlink/jdk.tools.jlink.internal.ImagePluginStack.operate(ImagePluginStack.java:194)
at jdk.jlink/jdk.tools.jlink.internal.JlinkTask.createImage(JlinkTask.java:423)
at jdk.jlink/jdk.tools.jlink.internal.JlinkTask.run(JlinkTask.java:286)
at jdk.jlink/jdk.tools.jlink.internal.Main.run(Main.java:56)
at jdk.jlink/jdk.tools.jlink.internal.Main.main(Main.java:34)
Error: jdk.tools.jlink.plugin.PluginException: ModuleTarget is malformed: No enum constant jdk.internal.util.Architecture.ARM
java.io.IOException: jdk.tools.jlink.plugin.PluginException: ModuleTarget is malformed: No enum constant jdk.internal.util.Architecture.ARM
at jdk.jlink/jdk.tools.jlink.internal.ImageFileCreator.writeImage(ImageFileCreator.java:173)
at jdk.jlink/jdk.tools.jlink.internal.ImageFileCreator.create(ImageFileCreator.java:100)
at jdk.jlink/jdk.tools.jlink.internal.JlinkTask$ImageHelper.retrieve(JlinkTask.java:860)
at jdk.jlink/jdk.tools.jlink.internal.ImagePluginStack.operate(ImagePluginStack.java:194)
at jdk.jlink/jdk.tools.jlink.internal.JlinkTask.createImage(JlinkTask.java:423)
at jdk.jlink/jdk.tools.jlink.internal.JlinkTask.run(JlinkTask.java:286)
at jdk.jlink/jdk.tools.jlink.internal.Main.run(Main.java:56)
at jdk.jlink/jdk.tools.jlink.internal.Main.main(Main.java:34)
Caused by: jdk.tools.jlink.plugin.PluginException: ModuleTarget is malformed: No enum constant jdk.internal.util.Architecture.ARM
at jdk.jlink/jdk.tools.jlink.builder.DefaultImageBuilder.storeFiles(DefaultImageBuilder.java:181)
at jdk.jlink/jdk.tools.jlink.internal.ImagePluginStack.storeFiles(ImagePluginStack.java:486)
at jdk.jlink/jdk.tools.jlink.internal.ImageFileCreator.writeImage(ImageFileCreator.java:168)