RFR: 8265173: [test] divert spurious log output away from stream under test in ProcessBuilder Basic test

[Roger Riggs]

The most recent intermittent failure showed that the error occurred during VM initialization.
Only the tty output was diverted, but not log output.
Add diversion of log output as well tty output.

Add `-Xlog:all=warning:stderr` and `-Xlog:all=warning:stdout` to correspond to 
`-XX:+DisplayVMOutputToStderr` and `-XX:+DisplayVMOutputToStdout`

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Commit messages:
 - 8265173: [test] divert spurious log output away from stream under test in ProcessBuilder Basic test

Changes: https://git.openjdk.java.net/jdk/pull/3492/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3492&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8265173
  Stats: 3 lines in 1 file changed: 2 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3492.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3492/head:pull/3492

PR: https://git.openjdk.java.net/jdk/pull/3492