RFR: CODETOOLS-7903329: Trace reasons to recompile extra property definition files

[Jonathan Gibbons]

Please review a small change to optionally trace why the "extra property definitions" files need to be (re)compiled.

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

Commit messages:
 - CODETOOLS-7903329: Trace reasons to recompile extra property definition files

Changes: https://git.openjdk.org/jtreg/pull/126/files
 Webrev: https://webrevs.openjdk.org/?repo=jtreg&pr=126&range=00
  Issue: https://bugs.openjdk.org/browse/CODETOOLS-7903329
  Stats: 19 lines in 2 files changed: 7 ins; 0 del; 12 mod
  Patch: https://git.openjdk.org/jtreg/pull/126.diff
  Fetch: git fetch https://git.openjdk.org/jtreg pull/126/head:pull/126

PR: https://git.openjdk.org/jtreg/pull/126