RFR: 8299337: The java.awt.image.ColorModel#pData field is unused

[Sergey Bylokhov]

I have found that we store the native pointer in the "java.awt.image.ColorModel#pData" field and never update/clean it. We can check how and when the native data is deallocated and reset the pointer, but it will be easy just to delete the field as unused.

-------------

Commit messages:
 - pData macosx
 - pData

Changes: https://git.openjdk.org/jdk/pull/11785/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11785&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8299337
  Stats: 13 lines in 5 files changed: 0 ins; 10 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/11785.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11785/head:pull/11785

PR: https://git.openjdk.org/jdk/pull/11785