RFR: 8269147: Update GStreamer to version 1.18.4

[Alexander Matveev]

- GStreamer updated to 1.18.4.
 - Tested on all platforms with all formats.

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Commit messages:
 - 8269147: Update GStreamer to version 1.18.4

Changes: https://git.openjdk.java.net/jfx/pull/541/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jfx&pr=541&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8269147
  Stats: 178 lines in 18 files changed: 82 ins; 3 del; 93 mod
  Patch: https://git.openjdk.java.net/jfx/pull/541.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/541/head:pull/541

PR: https://git.openjdk.java.net/jfx/pull/541