RFR: 8305846: Support compilation in Proc test utility

[Weijun Wang]

Enhance the `Proc` utility to support compilation.

-------------

Commit messages:
 - the fix

Changes: https://git.openjdk.org/jdk/pull/13425/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13425&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8305846
  Stats: 139 lines in 4 files changed: 121 ins; 8 del; 10 mod
  Patch: https://git.openjdk.org/jdk/pull/13425.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13425/head:pull/13425

PR: https://git.openjdk.org/jdk/pull/13425