RFR: 8294993: LingeredApp test update

[Kevin Walls]

There are a few changes we can make to better understand the LingeredApp test when it goes wrong:

startAppExactJvmOpts() should not try and call finishApp unless the process isAlive, that just creates a misleading exception.

waitAppReady() is really waitAppReadyOrCrashed(), and should not timeout immediately after the 1 second sleep, or we lose a second of our timeout value (not critical with a long timeout, but seems more honest).

Show how long we waited when startup/crashing times out.

Show how long a good startup takes, so we have a basic for comparison when it fails.

Show if there are hs_err/core/mdmp files in the working directory after startup/crash attempt.

Also, in open/test/lib/jdk/test/lib/util/CoreUtils.java:

"Move core file" often seems unnecessary, core/mdmp usually being created in the current directory. But getCoreFileLocation() performs Files.move() which takes enough time to not be a no-op.

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Commit messages:
 - Try stopApp (cooperative stop), then possibly finishApp (gather output)
 - Report time waited/taken, not the timeout value.
 - 8294993: LingeredApp test update

Changes: https://git.openjdk.org/jdk/pull/10613/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10613&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8294993
  Stats: 66 lines in 2 files changed: 45 ins; 10 del; 11 mod
  Patch: https://git.openjdk.org/jdk/pull/10613.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10613/head:pull/10613

PR: https://git.openjdk.org/jdk/pull/10613