RFR: 8347120: Launchers should not have java headers on include path

[Erik Joelsson]

The launcher src does not need any of the Java generated headers to compile, yet we are currently adding that directory to the include path. This is usually not a problem, but can cause a race that triggers unwanted recompilation in incremental builds (see bug description for details). This patch fixes this issue by not adding these directories to the include path when building the launcher.

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Commit messages:
 - Improved comment, copyright years
 - JDK-8347120

Changes: https://git.openjdk.org/jdk/pull/22953/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22953&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8347120
  Stats: 9 lines in 2 files changed: 6 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/22953.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22953/head:pull/22953

PR: https://git.openjdk.org/jdk/pull/22953