RFR: 8250778: [Lanai] Primitives rendered with metal on non-retina monitor are different as compared to OpenGL

[Ajit Ghaisas]

Issue : https://bugs.openjdk.java.net/browse/JDK-8250778
Fix :  Replicated pixel adjustments in Metal code similar to that of OpenGL code. Also, implemented DRAW_PIXEL
operation.

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Commit messages:
 - fix primitive rendering

Changes: https://git.openjdk.java.net/lanai/pull/70/files
 Webrev: https://webrevs.openjdk.java.net/lanai/70/webrev.00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8250778
  Stats: 116 lines in 2 files changed: 93 ins; 1 del; 22 mod
  Patch: https://git.openjdk.java.net/lanai/pull/70.diff
  Fetch: git fetch https://git.openjdk.java.net/lanai pull/70/head:pull/70

PR: https://git.openjdk.java.net/lanai/pull/70