RFR: 8374990: Check include folder of JDK image for unwanted files [v2]

[Matthias Baesken]

> We currently expect header files in the include folder of the jdk image.
> This should be checked by a test.
> (recently a check for the bin and lib folders has been added by [JDK-8374471](https://bugs.openjdk.org/browse/JDK-8374471))

Matthias Baesken has updated the pull request incrementally with one additional commit since the last revision:

  Add checking of jmods directory

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/29167/files
  - new: https://git.openjdk.org/jdk/pull/29167/files/c7b8a193..b7f26145

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29167&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29167&range=00-01

  Stats: 15 lines in 1 file changed: 15 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/29167.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29167/head:pull/29167

PR: https://git.openjdk.org/jdk/pull/29167