RFR: 8248129: Swingmark numbers are not good for Nimbus LAF

[Jayathirth D V]

Under this change we are removing MultiSample approach for Anti Aliasing and use shaders for the same.
With this change we are no seeing improvement in Swingmark numbers for Nimbus LAF and also there is significant improvement in RenderPerfTest numbers where we are drawing Parallelogram with AA.

This change also fixes https://bugs.openjdk.java.net/browse/JDK-8255212 as it is related AA state management.

Code related to MultiSampling in MTLTexturePool and MTLUtils is not removed because we might use that in future.
More analysis is captured in the bug.

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Commit messages:
 - Remove intermediate AA texture logic and add blending code
 - Merge branch 'master' into JDK-8248129
 - Add DrawAAParallelogram logic
 - Remove force commit
 - Initial FillAAParallelogram

Changes: https://git.openjdk.java.net/lanai/pull/124/files
 Webrev: https://webrevs.openjdk.java.net/?repo=lanai&pr=124&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8248129
  Stats: 465 lines in 6 files changed: 386 ins; 60 del; 19 mod
  Patch: https://git.openjdk.java.net/lanai/pull/124.diff
  Fetch: git fetch https://git.openjdk.java.net/lanai pull/124/head:pull/124

PR: https://git.openjdk.java.net/lanai/pull/124