RFR: 8294467: Fix sequence-point warnings in Hotspot

[Aleksey Shipilev]

There seem to be the only place in Hotspot where this warning fires, yet the warning is disabled wholesale for Hotspot. This is not good.

I can trace the addition of sequence-point exclusion to [JDK-8211029](https://bugs.openjdk.org/browse/JDK-8211029) (Sep 2018), yet the only place where it triggers introduced by [JDK-8259609](https://bugs.openjdk.org/browse/JDK-8259609) (Oct 2021). It seems other places were fixed meanwhile.

I believe the fixed place is just a simple leftover. Right, @rwestrel?

Additional testing:
 - [x] Linux x86_64 fastdebug `tier1`
 - [x]  Linux x86_64 fastdebug `tier2`
 - [x] The build matrix of:
   - GCC 10
   - {i686, x86_64, aarch64, powerpc64le, s390x, armhf, riscv64}
   - {server}
   - {release, fastdebug}

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Commit messages:
 - Fix

Changes: https://git.openjdk.org/jdk/pull/10454/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10454&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8294467
  Stats: 2 lines in 2 files changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/10454.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10454/head:pull/10454

PR: https://git.openjdk.org/jdk/pull/10454