[jdk19u] RFR: 8295926: RISC-V: C1: Fix LIRGenerator::do_LibmIntrinsic

[Xiaolin Zheng]

Clean backport from 20 for RISC-V backend: https://github.com/openjdk/jdk/commit/1fdbb1ba337b07dbcfb3c28c4fdeba74fee113dc

Tier1~2 testing passed, including the added jtreg test in this PR.

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Commit messages:
 - 8295926: RISC-V: C1: Fix LIRGenerator::do_LibmIntrinsic

Changes: https://git.openjdk.org/jdk19u/pull/70/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk19u&pr=70&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8295926
  Stats: 100 lines in 2 files changed: 95 ins; 4 del; 1 mod
  Patch: https://git.openjdk.org/jdk19u/pull/70.diff
  Fetch: git fetch https://git.openjdk.org/jdk19u pull/70/head:pull/70

PR: https://git.openjdk.org/jdk19u/pull/70