RFR: JDK-8323628: Update license on "pass-through" files [v2]

[Jonathan Gibbons]

> Please review an update to change the license used on those files that get written by `javadoc` into any generated API doc bundles. The license is changed to the Universal Permissive License in all situations.
> 
> A new test is added to verify the license is found on all appropriate files in the `resource-files` and `script-files` directories. One test, to detect and check CSS classes, was modified to ignore a false positive in the new comment in the stylesheet.css file.

Jonathan Gibbons has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains three commits:

 - Update src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/resources/stylesheet.css
   
   fix whitespace
   
   Co-authored-by: Pavel Rappo <32523691+pavelrappo at users.noreply.github.com>
 - Merge with upstream master
 - JDK-8323628: Update license on "pass-through" files

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Changes: https://git.openjdk.org/jdk/pull/17411/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17411&range=01
  Stats: 249 lines in 9 files changed: 129 ins; 108 del; 12 mod
  Patch: https://git.openjdk.org/jdk/pull/17411.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17411/head:pull/17411

PR: https://git.openjdk.org/jdk/pull/17411