Integrated: 8260640: Cleanup dead code and comments imported from OpenGL

[Jayathirth D V]

Clean up of unused code and removal/updation of comments imported from OpenGL.

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Commit messages:
 - cleanup commit

Changes: https://git.openjdk.java.net/lanai/pull/164/files
 Webrev: https://webrevs.openjdk.java.net/?repo=lanai&pr=164&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8260640
  Stats: 355 lines in 11 files changed: 0 ins; 340 del; 15 mod
  Patch: https://git.openjdk.java.net/lanai/pull/164.diff
  Fetch: git fetch https://git.openjdk.java.net/lanai pull/164/head:pull/164

PR: https://git.openjdk.java.net/lanai/pull/164