[jdk21u-dev] RFR: 8355569: Some nsk/jdi tests can glean the "main" thread by using the ClassPrepareEvent for the debuggee main class [v2]

[Goetz Lindenmaier]

> I backport this to keep the tests up to date and make later backports clean.

Goetz Lindenmaier has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains one new commit since the last revision:

  backport e2ae50d877b13b121912e2496af4b5209b315a05

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

Changes:
  - all: https://git.openjdk.org/jdk21u-dev/pull/2406/files
  - new: https://git.openjdk.org/jdk21u-dev/pull/2406/files/c8bcdf22..2c5b571c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=2406&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=2406&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/2406.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/2406/head:pull/2406

PR: https://git.openjdk.org/jdk21u-dev/pull/2406