RFR: 8270517: Add Zero support for LoongArch

[Ao Qi]

LoongArch is a new RISC ISA. This issue proposes adding Zero support for LoongArch. Only 64-bit support is proposed at present.

linux-loongarch64-zero-{release, fastdebug} build tested:

$ ./build/linux-loongarch64-zero-fastdebug/jdk/bin/java -version
openjdk version "18-internal" 2022-03-15
OpenJDK Runtime Environment (fastdebug build 18-internal+0-adhoc.aoqi.jdk)
OpenJDK 64-Bit Zero VM (fastdebug build 18-internal+0-adhoc.aoqi.jdk, interpreted mode)

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Commit messages:
 - 8270517: Add Zero support for LoongArch

Changes: https://git.openjdk.java.net/jdk/pull/4787/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4787&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8270517
  Stats: 22 lines in 3 files changed: 21 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4787.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4787/head:pull/4787

PR: https://git.openjdk.java.net/jdk/pull/4787