RFR: 8370708: RISC-V: Add VerifyStackAtCalls

[Robbin Ehn]

Hi, please consider.

Sanity tested, running t1.

Thanks, Robbin

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Commit messages:
 - Draft

Changes: https://git.openjdk.org/jdk/pull/28005/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=28005&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8370708
  Stats: 19 lines in 2 files changed: 13 ins; 4 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/28005.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28005/head:pull/28005

PR: https://git.openjdk.org/jdk/pull/28005