RFR: 7904153: JTReg should include crash log data in the failure node for xml reports [v2]

[William Kemper]

> The system we use (AWS CodeBuild) for running JTReg understands Junit/testNG xml files. For failed tests, it makes the text from the `failure` node easy to access from the UI. I appreciate that these xml files already have `system.err` and `system.out` nodes, but the tooling we use doesn't expose the data here (and I cannot change that tooling). Also, the current implementation takes the first section of `stderr` or `stdout`, which is often empty and comes from the `javac` portion of the test run.

William Kemper has updated the pull request incrementally with one additional commit since the last revision:

  Use the last output for a section to get the failure. Only do this for the failure node

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Changes:
  - all: https://git.openjdk.org/jtreg/pull/316/files
  - new: https://git.openjdk.org/jtreg/pull/316/files/85d879f7..ec9758eb

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jtreg&pr=316&range=01
 - incr: https://webrevs.openjdk.org/?repo=jtreg&pr=316&range=00-01

  Stats: 41 lines in 2 files changed: 21 ins; 0 del; 20 mod
  Patch: https://git.openjdk.org/jtreg/pull/316.diff
  Fetch: git fetch https://git.openjdk.org/jtreg.git pull/316/head:pull/316

PR: https://git.openjdk.org/jtreg/pull/316