RFR: 8337550: Add documentation to TestOutOfMemoryDuringInit.java

[Albert Mingkun Yang]

Comment-only patch to make the intention of the test explicit.

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Commit messages:
 - add-doc

Changes: https://git.openjdk.org/jdk/pull/20405/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20405&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8337550
  Stats: 4 lines in 1 file changed: 4 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/20405.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20405/head:pull/20405

PR: https://git.openjdk.org/jdk/pull/20405