[OpenJDK 2D-Dev] RFR: 8262392: Update Mesa 3-D Headers to version 21.0.3

[Phil Race]

Upgrades OpenGL header files to the latest Mesa project ones.
Build+test looks fine.

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

Commit messages:
 - 8262392: Update Mesa 3-D Headers to version 21.0.3

Changes: https://git.openjdk.java.net/jdk/pull/3854/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3854&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8262392
  Stats: 144 lines in 6 files changed: 100 ins; 21 del; 23 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3854.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3854/head:pull/3854

PR: https://git.openjdk.java.net/jdk/pull/3854