RFR: 8237078: Media build code broken on XCode 11

[Johan Vos]

Fix JDK-8237078
replace the objc_msgSend call with a direct objC call.
The fix works on XCode 10.1 and XCode 11.3

Tested using
java  -Djfxmedia.platforms=OSXPlatform
with MediaPlayer playing an mp3.

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Commits:
 - 33582c1d: Fix 8237078 : media build code broken on XCode 11

Changes: https://git.openjdk.java.net/jfx/pull/90/files
 Webrev: https://webrevs.openjdk.java.net/jfx/90/webrev.00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8237078
  Stats: 3 lines in 1 file changed: 0 ins; 2 del; 1 mod
  Patch: https://git.openjdk.java.net/jfx/pull/90.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/90/head:pull/90

PR: https://git.openjdk.java.net/jfx/pull/90