RFR: 8283218: Update GStreamer to 1.20.1 [v5]

[Kevin Rushforth]

On Wed, 20 Apr 2022 23:08:00 GMT, Alexander Matveev <almatvee at openjdk.org> wrote:

>> - GStreamer updated to 1.20.1 and GLib updated to 2.72.0.
>> - No changes to our code, except in GstAudioSpectrum.cpp g_atomic_pointer_compare_and_exchange() was changed to g_atomic_pointer_set(). For some reason I was not able to get code compiled with g_atomic_pointer_compare_and_exchange() used from C++ code. Also, I do not see a need to use g_atomic_pointer_compare_and_exchange(), since m_pHolder always equals to old_holder.
>> - Tested on all platforms with all supported media streams.
>
> Alexander Matveev has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8283218: Update GStreamer to 1.20.1 [v5]

Answering my own question from above, I was able to take a `gstreamer-lite` binary built on Oracle Linux 7.x and run it on my Ubuntu 16.04 system, so it looks like we are good to go.

Alexander or I will file a follow-on bug to build and ship `glib-lite` on Linux. It will allow some of the custom code to be reverted, and will avoid this problem the next time we update GLib. It also matches what we do for the other platforms (and what we do for Linux on Oracle's JDK 8u releases, so we have a data point that shows it to be a feasible approach).

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Marked as reviewed by kcr (Lead).

PR: https://git.openjdk.java.net/jfx/pull/768