RFR: 2200: The jdk/internal/javac package should be mapped to the compiler label

[Jan Lahoda]

Originally, `jdk/internal/PreviewFeature.java` was mapped to the compiler label, but this has been moved into `jdk/internal/javac`, breaking the mapping. Re-mapping `jdk/internal/javac` back to compiler. Keeping the mapping to core-libs, partially because changes there may be relevant to core-libs as well.

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Commit messages:
 - 2200: The jdk/internal/javac package should be mapped to the compiler label

Changes: https://git.openjdk.org/skara/pull/1621/files
  Webrev: https://webrevs.openjdk.org/?repo=skara&pr=1621&range=00
  Issue: https://bugs.openjdk.org/browse/SKARA-2200
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/skara/pull/1621.diff
  Fetch: git fetch https://git.openjdk.org/skara.git pull/1621/head:pull/1621

PR: https://git.openjdk.org/skara/pull/1621