RFR: 8349851: RISCV: Call VM leaf can use movptr2

[Robbin Ehn]

Hi, please consider.

There should be a small speed up to vm leafs.
We can scratch t2 here as we just pushed it. (maybe I should have used t0)

Passes t1

/Robbin

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Commit messages:
 - Changes

Changes: https://git.openjdk.org/jdk/pull/23565/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23565&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8349851
  Stats: 3 lines in 1 file changed: 2 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/23565.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23565/head:pull/23565

PR: https://git.openjdk.org/jdk/pull/23565