RFR: 8347617: Shenandoah: Use consistent name for update references phase

[William Kemper]

Trivial merge conflict.

-------------

Commit messages:
 - Backport 0330ca4221ba7bacb0eaeed1a8cdc3d5c3653a83

Changes: https://git.openjdk.org/shenandoah-jdk21u/pull/163/files
  Webrev: https://webrevs.openjdk.org/?repo=shenandoah-jdk21u&pr=163&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8347617
  Stats: 64 lines in 18 files changed: 0 ins; 0 del; 64 mod
  Patch: https://git.openjdk.org/shenandoah-jdk21u/pull/163.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/163/head:pull/163

PR: https://git.openjdk.org/shenandoah-jdk21u/pull/163