[OpenJDK 2D-Dev] RFR: 8252758: Lanai: Optimize index calculation while copying glyphs

[Jayathirth D V]

Loop optimization while copying glyph content.
J2DDemo, SwingSet2 and Font2DTest are green.

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Commit messages:
 - 8252758: Lanai: Optimize index calculation while copying glyphs

Changes: https://git.openjdk.java.net/jdk/pull/3883/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3883&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8252758
  Stats: 15 lines in 1 file changed: 0 ins; 0 del; 15 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3883.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3883/head:pull/3883

PR: https://git.openjdk.java.net/jdk/pull/3883