RFR: Merge jdk:master [v2]

[J.Duke]

> Hi all,
> 
> this is an _automatically_ generated pull request to notify you that there are 58 commits from the branch
> `jdk:master`that can **not** be merged into the branch `master`:
> The following file contains merge conflicts:
> 
> - .jcheck/conf
> 
> All Committers in this [project](https://openjdk.java.net/census#Optional[panama]) have access to my [personal
> fork](https://github.com/openjdk-bot/panama-foreign) 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/panama-foreign](https://github.com/openjdk/panama-foreign) repository.  # Ensure target branch is up to date $
> git checkout master $ git pull https://github.com/openjdk/panama-foreign master
> 
> # Fetch and checkout the branch for this pull request
> $ git fetch https://github.com/openjdk-bot/panama-foreign +53:openjdk-bot-53
> $ git checkout openjdk-bot-53
> 
> # 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/panama-foreign openjdk-bot-53:53
> 
> _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

J. Duke has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains
59 commits:

 - Merge branch 'master' into openjdk-bot-53
 - 8253008: Remove develop flags TraceLongCompiles/LongCompileThreshold
   
   Reviewed-by: shade, dholmes, adityam
 - 8253026: Remove dummy call to gc alot from VM Thread
   
   Reviewed-by: coleenp, dholmes
 - 8243208: Clean up JVMFlag implementation
   
   Reviewed-by: dholmes, coleenp, gziemski
 - 8252406: Introduce Thread::as_Java_thread() convenience function
   
   Reviewed-by: shade, coleenp, kbarrett, dcubed
 - 8171303: sun/java2d/pipe/InterpolationQualityTest.java fails on Windows & Linux
   
   Reviewed-by: prr, psadhukhan, kcr
 - 7183828: Invalid Image Variant when using anything other than BufferedImage
   
   Reviewed-by: prr
 - 8252817: Cleanup the classes in the java.awt.color package
   
   Reviewed-by: jdv, pbansal
 - 8252919: JDK built with --enable-cds=no fails with NoClassDefFoundError
   
   Reviewed-by: minqi, sundar, alanb, redestad
 - 8252830: Correct missing javadoc comments in java.rmi module
   
   Reviewed-by: dfuchs, lancea, smarks, chegar
 - ... and 49 more: https://git.openjdk.java.net/panama-foreign/compare/bc0381f1...bd10a925

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

Changes: https://git.openjdk.java.net/panama-foreign/pull/321/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=321&range=01
  Stats: 11479 lines in 469 files changed: 7105 ins; 1924 del; 2450 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/321.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/321/head:pull/321

PR: https://git.openjdk.java.net/panama-foreign/pull/321