RFR: Merge jdk:master

[J.Duke]

Hi all,

this is an _automatically_ generated pull request to notify you that there are 17 commits from the branch
`jdk:master`that can **not** be merged into the branch `master`:

The following files contains merge conflicts:

- make/autoconf/platform.m4
- make/modules/jdk.net/Lib.gmk

All Committers in this [project](https://openjdk.java.net/census#Optional[mobile]) have access to my [personal
fork](https://github.com/openjdk-bot/mobile) and can therefore help resolve these merge conflicts (you may want to
coordinate who should do this). The following paragraphs will give an example on how to solve these merge conflicts and
push the resulting merge commit to this pull request. The below commands should be run in a local clone of your
[personal fork](https://wiki.openjdk.java.net/display/skara#Skara-Personalforks) of the
[openjdk/mobile](https://github.com/openjdk/mobile) repository.

# Ensure target branch is up to date
$ git checkout master
$ git pull https://github.com/openjdk/mobile master

# Fetch and checkout the branch for this pull request
$ git fetch https://github.com/openjdk-bot/mobile +2:openjdk-bot-2
$ git checkout openjdk-bot-2

# Merge the target branch
$ git merge master

When you have resolved the conflicts resulting from the `git merge` command above, run the following commands to create
a merge commit:

$ git add paths/to/files/with/conflicts
$ git commit -m 'Merge jdk:master'


When you have created the merge commit, run the following command to push the merge commit to this pull request:

$ git push https://github.com/openjdk-bot/mobile openjdk-bot-2:2

_Note_: if you are using SSH to push commits to GitHub, then change the URL in the above `git push` command accordingly.

Thanks,
J. Duke

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

Commit messages:
 - Merge
 - 8245518: Problem list java/net/SocketOption/AfterClose.java
 - 8238592: JFR: Crash when dumping paths to gc roots on deep heaps
 - Added tag jdk-15+24 for changeset 497fd9f9129c
 - Merge
 - 8244224: Implementation of JEP 381: Remove the Solaris and SPARC Ports
 - 8235921: jdk/jfr/event/oldobject/TestLargeRootSet.java times out with debug bits
 - Merge
 - 8233553: [TESTBUG] JSpinner test bug4973721.java fails on MacOS
 - 6949753: [TEST BUG]: java/awt/print/PageFormat/PDialogTest.java needs update by removing a infinite loop
 - ... and 7 more: https://git.openjdk.java.net/mobile/compare/822ec45b...270674ce

The webrev contains the conflicts with master:
 - merge conflicts: https://webrevs.openjdk.java.net/mobile/6/webrev.00.conflicts

Changes: https://git.openjdk.java.net/mobile/pull/6/files
  Stats: 128991 lines in 988 files changed: 806 ins; 127003 del; 1182 mod
  Patch: https://git.openjdk.java.net/mobile/pull/6.diff
  Fetch: git fetch https://git.openjdk.java.net/mobile pull/6/head:pull/6

PR: https://git.openjdk.java.net/mobile/pull/6