git: openjdk/jdk: 8262392: Update Mesa 3-D Headers to version 21.0.3

[Phil Race]

Changeset: 138d573c
Author:    Phil Race <prr at openjdk.org>
Date:      2021-05-05 19:39:15 +0000
URL:       https://git.openjdk.java.net/jdk/commit/138d573c3567e9a51b1ac2b1de89b41c4b51ae93

8262392: Update Mesa 3-D Headers to version 21.0.3

Reviewed-by: serb, jdv, kcr

! src/java.desktop/share/legal/mesa3d.md
! src/java.desktop/share/native/common/java2d/opengl/J2D_GL/gl.h
! src/java.desktop/share/native/common/java2d/opengl/J2D_GL/glext.h
! src/java.desktop/unix/native/common/java2d/opengl/J2D_GL/glx.h
! src/java.desktop/unix/native/common/java2d/opengl/J2D_GL/glxext.h
! src/java.desktop/windows/native/libawt/java2d/opengl/J2D_GL/wglext.h