RFR: 8260431: com/sun/jdi/JdbOptions.java failed with "RuntimeException: 'prop[boo] = >foo<' missing from stdout/stderr"

[Alex Menkov]

The test expects debuggee output in jdb output stream.
But jdb redirects debuggee output asynchronously so sometimes it's incomplete or mixed with jdb output.
The fix updates debuggee to print output to file and read/analyze it after jdb (and debuggee) exits.

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Commit messages:
 - Redirect debuggee output to file

Changes: https://git.openjdk.java.net/jdk/pull/2322/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2322&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8260431
  Stats: 42 lines in 1 file changed: 27 ins; 3 del; 12 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2322.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2322/head:pull/2322

PR: https://git.openjdk.java.net/jdk/pull/2322