[Rev 01] RFR: 8234474: [macos 10.15] Crash in file dialog in sandbox mode

[Kevin Rushforth]

> This PR is a fix for [JDK-8234474](https://bugs.openjdk.java.net/browse/JDK-8234474), a crash in the code that shows a file open or save dialog.
> 
> In order to provide additional support for Copy (CMD-C), Cut (CMD-X), and Paste (CMD-V), the Glass implementation for displaying a file open or save dialog subclasses NSSavePanel or NSOpenPanel to add this support. When the application is running in sandboxed mode, the dialogs are shown out-of-process by the "powerbox". In this mode, attempting to use our subclass results in a security exception. Previously, we added code to detect whether we were running in a sandbox as a fix for [JDK-8092977](https://bugs.openjdk.java.net/browse/JDK-8092977); we now use NSSavePanel or NSOpenPanel directly when in sandboxed mode.
> 
> Starting with macOS 10.15 (Catalina) Apple always displays file dialogs out-of-process via powerbox, so our use of a subclass is ineffective. Further, we have reports of some cases where we crash even though our sandbox detection code doesn't indicate that we are running in a sandbox.
> 
> Since there is no point in trying to use our subclasses on macOS 10.15 or later, I propose to fix this bug by changing the logic so that we use NSSavePanel or NSOpenPanel directly in either of the following conditions:
> 
> 1) the app is running in sandbox mode
> OR
> 2) The platform is macOS 10.15 or later

The pull request has been updated with 1 additional commit.

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

Added commits:
 - b13da6f7: Update copyright year to 2020

Changes:
  - all: https://git.openjdk.java.net/jfx/pull/70/files
  - new: https://git.openjdk.java.net/jfx/pull/70/files/dca394e6..b13da6f7

Webrevs:
 - full: https://webrevs.openjdk.java.net/jfx/70/webrev.01
 - incr: https://webrevs.openjdk.java.net/jfx/70/webrev.00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jfx/pull/70.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/70/head:pull/70

PR: https://git.openjdk.java.net/jfx/pull/70