[jdk11u-dev] RFR: 8259530: Generated docs contain MIT/GPL-licenced works without reproducing the licence

[Kimura Yukihiro]

I would like to backport
JDK-8259530: Generated docs contain MIT/GPL-licenced works without reproducing the licence.
The original patch does not apply cleanly to 11u. 
Because the original patch has switch expressions which can not be used in 11u,
and it has the Class jdk.javadoc.internal.doclets.formats.html.HtmlOptions which is not defined in 11u. 
There is no risk, because the logic around the changes is the same as jdk17. 
I confirmed the following test and all langtool tests.
test/langtools/jdk/javadoc/doclet/testLegalNotices/TestLegalNotices.java

Could anyone review the fix please?

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Commit messages:
 - Merge branch 'openjdk:master' into 8259530
 - Backport e9f3e325c274f19b0f6eceea2367708e3be689e9

Changes: https://git.openjdk.org/jdk11u-dev/pull/1805/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=1805&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8259530
  Stats: 288 lines in 11 files changed: 281 ins; 0 del; 7 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/1805.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev pull/1805/head:pull/1805

PR: https://git.openjdk.org/jdk11u-dev/pull/1805