RFR: 8296975: RISC-V: Enable UseRVA20U64 profile by default

[Xiaolin Zheng]

The main purpose is to turn the option `UseRVC` on by default before JDK20 RDP 1. As per discussions [1], we can enable UseRVA20U64[2] by default to fulfill this.

[1] https://mail.openjdk.org/pipermail/riscv-port-dev/2022-November/000668.html
[2] https://github.com/openjdk/jdk/blob/873eccde01895de06e2216f6838d52d07188addd/src/hotspot/cpu/riscv/vm_version_riscv.cpp#L39-L44

Thanks,
Xiaolin

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Commit messages:
 - Merge remote-tracking branch 'github-openjdk/master' into rvc-by-default
 - Enable UseRVA20U64 by default and move my home
 - Revert "RVC by default"
 - Revert "Move my home"
 - Move my home
 - RVC by default

Changes: https://git.openjdk.org/jdk/pull/11155/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11155&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8296975
  Stats: 3 lines in 1 file changed: 1 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/11155.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11155/head:pull/11155

PR: https://git.openjdk.org/jdk/pull/11155