RFR: 8292250: Create test for co-located JDI MethodEntry, Step, and Breakpoint events [v3]

[Chris Plummer]

> We currently have no tests for co-located MethodEntry, Step, and Breakpoint events. We should make sure they are being properly co-located as described in the JDI spec, and also do special test cases for [JDK-8292217](https://bugs.openjdk.org/browse/JDK-8292217).
> 
> https://docs.oracle.com/en/java/javase/17/docs/api/jdk.jdi/com/sun/jdi/event/EventSet.html
> 
> And sorry in advance that the logic is a bit hard to follow in this test due to having multiple test cases, and dealing with the async nature of JDI testing. All I can say is that is used to be a lot worse before I did multiple passes to improve it.

Chris Plummer has updated the pull request incrementally with one additional commit since the last revision:

  Some minor fixes and improvements.

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/9840/files
  - new: https://git.openjdk.org/jdk/pull/9840/files/6bf3dd79..81c7cdca

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9840&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9840&range=01-02

  Stats: 10 lines in 1 file changed: 4 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/9840.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9840/head:pull/9840

PR: https://git.openjdk.org/jdk/pull/9840