RFR: 8312307: Obsoleted code in hb-jdk-font.cc

[Phil Race]

Clean up some un-used code in the 2D native font code that interfaces to libharfbuzz

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Commit messages:
 - 8312307

Changes: https://git.openjdk.org/jdk/pull/17022/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17022&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8312307
  Stats: 16 lines in 2 files changed: 0 ins; 16 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/17022.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17022/head:pull/17022

PR: https://git.openjdk.org/jdk/pull/17022