RFR: 8282493: Add --with-jcov-modules convenience option

[Magnus Ihse Bursie]

Allow the user to set "--with-jcov-modules=java.desktop", instead of "--with-jcov-filters=--include-modules java.desktop", since this is one of the common use cases for the filtering.

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Commit messages:
 - Also fix RepGen
 - Update with correct syntax + debug support
 - 8282493: Add --with-jcov-modules convenience option

Changes: https://git.openjdk.org/jdk/pull/24481/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24481&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8282493
  Stats: 30 lines in 4 files changed: 23 ins; 0 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/24481.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24481/head:pull/24481

PR: https://git.openjdk.org/jdk/pull/24481