[jdk17u-dev] RFR: 8298974: Add ftcolor.c to imported freetype sources

[Martin Doerr]

Backport of [JDK-8298974](https://bugs.openjdk.org/browse/JDK-8298974).

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Commit messages:
 - Backport 05f9e7676ea457cd5ef44acca9a1706b5dd0d093

Changes: https://git.openjdk.org/jdk17u-dev/pull/1496/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1496&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8298974
  Stats: 156 lines in 1 file changed: 156 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1496.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/1496/head:pull/1496

PR: https://git.openjdk.org/jdk17u-dev/pull/1496