RFR: 8262396: Update Mesa 3-D Headers to version 21.0.3

[Kevin Rushforth]

Update OpenGL headers to latest versions from Mesa project. I ran a sanity test on all three platforms. I also checked the diffs against the Java2D patch in openjdk/jdk#3854 and they match, excluding the Java2D-specific ifdefs.

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Commit messages:
 - 8262396: Update Mesa 3-D Headers to version 21.0.3

Changes: https://git.openjdk.java.net/jfx/pull/486/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jfx&pr=486&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8262396
  Stats: 140 lines in 6 files changed: 100 ins; 18 del; 22 mod
  Patch: https://git.openjdk.java.net/jfx/pull/486.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/486/head:pull/486

PR: https://git.openjdk.java.net/jfx/pull/486