[riscv-port-jdk11u:riscv-port] RFR: 8326960: GHA: RISC-V sysroot cannot be debootstrapped due to ongoing Debian t64 transition

[Fei Yang]

Makes GHA cross-compilation jobs clean again. Applies cleanly. GHA passes.

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Commit messages:
 - backport

Changes: https://git.openjdk.org/riscv-port-jdk11u/pull/14/files
  Webrev: https://webrevs.openjdk.org/?repo=riscv-port-jdk11u&pr=14&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8326960
  Stats: 15 lines in 1 file changed: 14 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/riscv-port-jdk11u/pull/14.diff
  Fetch: git fetch https://git.openjdk.org/riscv-port-jdk11u.git pull/14/head:pull/14

PR: https://git.openjdk.org/riscv-port-jdk11u/pull/14