RFR: 8245025: MoveAndUpdateClosure::do_addr calls function with side-effects in an assert

[Albert Mingkun Yang]

Make the assertion code side-effect free.

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

Commit messages:
 - assert

Changes: https://git.openjdk.java.net/jdk/pull/2898/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2898&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8245025
  Stats: 37 lines in 2 files changed: 19 ins; 3 del; 15 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2898.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2898/head:pull/2898

PR: https://git.openjdk.java.net/jdk/pull/2898