TransportChangePasswordActionTests#testIncorrectPasswordHashingAlgorithm fails with assertion error.

[jtibshirani]

The failure reliably reproduces for me locally, and may be related to the recent change to password hashing: #31234.

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Link to the build: https://elasticsearch-ci.elastic.co/job/elastic+elasticsearch+master+multijob-unix-compatibility/os=oraclelinux/2527/console

Command to reproduce:

./gradlew :x-pack:plugin:security:test \
  -Dtests.seed=E93A5B2F1C4967B6 \
  -Dtests.class=org.elasticsearch.xpack.security.action.user.TransportChangePasswordActionTests \
  -Dtests.method="testIncorrectPasswordHashingAlgorithm" \
  -Dtests.security.manager=true \
  -Dtests.locale=fr-LU \
  -Dtests.timezone=America/Guadeloupe

Relevant excerpt from the logs:

FAILURE 1.15s | TransportChangePasswordActionTests.testIncorrectPasswordHashingAlgorithm <<< FAILURES!
   > Throwable #1: java.lang.AssertionError: 
   > Expected: an instance of java.lang.IllegalArgumentException
   >      but: null
   >    at __randomizedtesting.SeedInfo.seed([B944BC5A5B893131:84873E560B50D358]:0)
   >    at org.hamcrest.MatcherAssert.assertThat(MatcherAssert.java:20)
   >    at org.elasticsearch.xpack.security.action.user.TransportChangePasswordActionTests.testIncorrectPasswordHashingAlgorithm(TransportChangePasswordActionTests.java:184)
   >    at java.lang.Thread.run(Thread.java:748)

[elasticmachine]

Pinging @elastic/es-security