RFR: 8314330: java/foreign tests should respect vm flags when start new processes

[Leonid Mesnik]

The test helper which spawn new jvms is updated to start them using VM flags for testing.

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Commit messages:
 - 8314330: java/foreign tests should respect vm flags when start new processes

Changes: https://git.openjdk.org/jdk/pull/15302/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15302&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8314330
  Stats: 10 lines in 1 file changed: 1 ins; 7 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/15302.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15302/head:pull/15302

PR: https://git.openjdk.org/jdk/pull/15302