RFR: 8336479: Provide Process.waitFor(Duration)

[Naoto Sato]

Proposing a new overload method for `Process#waitFor()` which takes a `Duration` for the timeout value. This will reduce the possibility for making mistakes with the `TimeUnit` in the other overload method. A corresponding CSR has also been drafted.

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Commit messages:
 - initial commit

Changes: https://git.openjdk.org/jdk/pull/20220/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20220&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8336479
  Stats: 109 lines in 2 files changed: 106 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/20220.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20220/head:pull/20220

PR: https://git.openjdk.org/jdk/pull/20220