RFR: 8293214: Add support for Linux/LoongArch64

[Ao Qi]

LoongArch is a new RISC ISA. This issue proposes adding support for Linux/LoongArch64. Upstream WebKit for LoongArch64 support is not ready, but the OpenJFX part is simple and ready. When the LoongArch64 supported Webkit is updated to OpenJFX, it is supposed to work.

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Commit messages:
 - 8293214: Add support for Linux/LoongArch64

Changes: https://git.openjdk.org/jfx/pull/888/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=888&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8293214
  Stats: 26 lines in 4 files changed: 15 ins; 0 del; 11 mod
  Patch: https://git.openjdk.org/jfx/pull/888.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/888/head:pull/888

PR: https://git.openjdk.org/jfx/pull/888