RFR: 8345047: RISC-V: Remove explicit use of AvoidUnalignedAccesses in interpreter

[Fei Yang]

Hi, please consider this small interpreter cleanup change.

The use of AvoidUnalignedAccesses option for these cases doen't much sense to me.
MacroAssembler routines like `revb_h_h_u` and `revb_h_h` will emit 5 instructions when Zbb extension is not available. This is more than the case when AvoidUnalignedAccesses option is true. After this change, we always emit 4 instructions compared to 3 instructions in the case when we have Zbb extension. But I don't think it will make a difference.

Testing on linux-riscv64 platform:
- [x] tier1 (release)

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Commit messages:
 - 8345047: RISC-V: Remove explicit use of AvoidUnalignedAccesses in interpreter

Changes: https://git.openjdk.org/jdk/pull/22387/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22387&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8345047
  Stats: 36 lines in 2 files changed: 0 ins; 23 del; 13 mod
  Patch: https://git.openjdk.org/jdk/pull/22387.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22387/head:pull/22387

PR: https://git.openjdk.org/jdk/pull/22387