RFR: 8294400: Provide media support for libavcodec version 59 [v2]

[Alexander Matveev]

> - Added support for libavcodec 59.
>  - libavcodec 59 removed several deprecated APIs and avplugin code was updated to use replacement APIs instead.
>  - No changes to avplugin when used with 58 or below.
>  - Note: Support for libavcodec 59 was added based on ffmpeg only. libav does not have version 59.

Alexander Matveev has updated the pull request incrementally with one additional commit since the last revision:

  8294400: Provide media support for libavcodec version 59 [v2]

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

Changes:
  - all: https://git.openjdk.org/jfx/pull/932/files
  - new: https://git.openjdk.org/jfx/pull/932/files/bb4cead0..86fd01fc

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=932&range=01
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=932&range=00-01

  Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jfx/pull/932.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/932/head:pull/932

PR: https://git.openjdk.org/jfx/pull/932