RFR: 8207333: [Linux, macOS] Column sorting is triggered always after context menu request on table header [v5]

[Jose Pereda]

> Note: The JBS issue [JDK-8207333](https://bugs.openjdk.org/browse/JDK-8207333) refers to Linux, but it happens on macOS too. 
> 
> When a TableColumn has a ContextMenu, if the user right clicks on the tableColumnHeader, the ContextMenu shows up, but, as described on the issue, on macOS and Linux, the table gets sorted as well.
> 
> Currently, `TableColumnHeader#mouseReleasedHandler` checks for `MouseEvent::isPopupTriggered`, but it doesn't have a check on `mousePressed`. However,  it can be seen that a right click on the header has the following values for `MouseEvent:: isPopupTriggered` on the different platforms and mouse pressed and released events:
> 
> | isPopupTriggered on: | Windows  | macOS | Linux |
> | ------------- | ------------- | ------------- | ------------- |
> | mousePressed  | false  | true | true |
> | mouseReleased  | true  | false | false |
> 
> Also, the JavaDoc for `MouseEvent::isPopupTriggered` clearly states that:
> 
>> **Note**: Popup menus are triggered differently on different systems. Therefore, `popupTrigger` should be checked in both `onMousePressed` and `mouseReleased` for proper cross-platform functionality.
> 
> Therefore, this PR adds a check to `MouseEvent::isPopupTrigger` in the mouse pressed event, that can be used later on to cancel the header sorting when the mouse released event happens.
> 
> Also a system test has been added. It fails on macOS and Linux, and passes on Windows before this PR, and passes on the three platforms with this PR.

Jose Pereda has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains five additional commits since the last revision:

 - Merge branch 'master' into 8207333-contextmenusort
 - remove white space
 - keep column drag lock
 - Prevent drag or start sorting on if popup is triggered, test ctrl+left click on macOS
 - Check popupTrigger on mouse pressed too for tableColumnHeaders

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

Changes:
  - all: https://git.openjdk.org/jfx/pull/1754/files
  - new: https://git.openjdk.org/jfx/pull/1754/files/ad478220..bd73bcb7

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1754&range=04
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1754&range=03-04

  Stats: 129823 lines in 393 files changed: 34627 ins; 52503 del; 42693 mod
  Patch: https://git.openjdk.org/jfx/pull/1754.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1754/head:pull/1754

PR: https://git.openjdk.org/jfx/pull/1754