RFR: JDK-8288368: simplify code in ValueTaglet, remove redundant code

[Jonathan Gibbons]

Please review an almost trivial cleanup change, to eliminate the call to an ill-considered method in Utils, and then remove the method itself.

Verified that there is no significant change in the generated docs as a result off the change. (Just changes in timestamp/version info).

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Commit messages:
 - JDK-8288368: simplify code in ValueTaglet, remove redundant code

Changes: https://git.openjdk.org/jdk/pull/9149/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=9149&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8288368
  Stats: 25 lines in 2 files changed: 0 ins; 24 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/9149.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9149/head:pull/9149

PR: https://git.openjdk.org/jdk/pull/9149