[jdk11u-dev] RFR: 8265173: [test] divert spurious log output away from stream under test in ProcessBuilder Basic test

[Goetz Lindenmaier]

I backport this for parity with 11.0.14-oracle.

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Commit messages:
 - Backport 7b61a426e0837bde4885bd53397bba6b0939382f

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/470/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=470&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/jdk11u-dev/pull/470.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/470/head:pull/470

PR: https://git.openjdk.java.net/jdk11u-dev/pull/470