RFR: 4884570: StreamPrintService.isAttributeValueSupported does not work properly for SheetCollate [v3]

[Phil Race]

> This fixes a longstanding consistency issue where the Postscript StreamPrintService would report SheetCollate.UNCOLLATED in a list of supported values then report it was not supported under the same conditions.

Phil Race has updated the pull request incrementally with one additional commit since the last revision:

   4884570: StreamPrintService.isAttributeValueSupported does not work properly for SheetCollate

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/6963/files
  - new: https://git.openjdk.java.net/jdk/pull/6963/files/69f49feb..7722c2c3

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=6963&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=6963&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6963.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6963/head:pull/6963

PR: https://git.openjdk.java.net/jdk/pull/6963