[jdk11u-dev] RFR: 8298974: Add ftcolor.c to imported freetype sources

[Goetz Lindenmaier]

I backport this for parity with 11.0.21-oracle.

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Commit messages:
 - Backport 05f9e7676ea457cd5ef44acca9a1706b5dd0d093

Changes: https://git.openjdk.org/jdk11u-dev/pull/2008/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=2008&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/jdk11u-dev/pull/2008.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev.git pull/2008/head:pull/2008

PR: https://git.openjdk.org/jdk11u-dev/pull/2008