[jdk17u-dev] RFR: 8283929: GHA: Add RISC-V build config

[Feilong Jiang]

Hi,
I would like to backport [JDK-8283929](https://bugs.openjdk.org/browse/JDK-8283929) to enable cross-compiling for linux-riscv64 on jdk17u-dev, as #1427 has integrated.

The backport is not clean:
1. jdk17u-dev CI uses Ubuntu focal (20.04) which doesn't have up-to-date debian-ports-archive keyring [1], so I removed the `debian-ports-archive-keyring` installing and settings.

Changes tested with GHA on my personal branch and passed the cross-compiling for linux-riscv64 [2].

1. https://bugs.launchpad.net/ubuntu/+source/debian-ports-archive-keyring/+bug/1969202
2. https://github.com/feilongjiang/jdk17u-dev/actions/runs/5508731228/jobs/10041643179

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Commit messages:
 - Backport 85d4b49151e9529051f1ed344749a487d3e92165

Changes: https://git.openjdk.org/jdk17u-dev/pull/1562/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1562&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8283929
  Stats: 24 lines in 1 file changed: 18 ins; 4 del; 2 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1562.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/1562/head:pull/1562

PR: https://git.openjdk.org/jdk17u-dev/pull/1562