[OpenJDK 2D-Dev] RFR: 8263984: Invalidate printServices when there are no printers

[Alexey Ivanov]

When `getAllPrinterNames()` returns null, the list of `printServices` is assigned a new empty array without invalidating old services which were in the array before.

The old print services should be invalidated.

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Commit messages:
 - 8263984: Invalidate printServices when there are no printers

Changes: https://git.openjdk.java.net/jdk/pull/3151/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3151&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8263984
  Stats: 8 lines in 1 file changed: 6 ins; 1 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3151.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3151/head:pull/3151

PR: https://git.openjdk.java.net/jdk/pull/3151