RFR: 8310105: LoongArch64 builds are broken after JDK-8304913

[Ao Qi]

LoongArch64 Zero builds are broken after [JDK-8304913](https://bugs.openjdk.org/browse/JDK-8304913):

jdk.tools.jlink.plugin.PluginException: ModuleTarget is malformed: No enum constant jdk.internal.util.Architecture.LOONGARCH64
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.LOONGARCH64


Builds tested: LoongArch64 Zero, both release and fastdebug.

If this patch conflicts with #14471, I will rebase after #14471 is integrated.

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Commit messages:
 - 8310105: LoongArch64 builds are broken after JDK-8304913

Changes: https://git.openjdk.org/jdk/pull/14482/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14482&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8310105
  Stats: 13 lines in 3 files changed: 13 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/14482.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14482/head:pull/14482

PR: https://git.openjdk.org/jdk/pull/14482