RFR: JDK-8255262: Remove use of legacy custom @spec tag

[Jonathan Gibbons]

The change is (just) to remove legacy usages of a JDK-private custom tag.

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Commit messages:
 - JDK-8255262: Remove use of legacy custom @spec tag

Changes: https://git.openjdk.java.net/jdk/pull/814/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=814&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8255262
  Stats: 209 lines in 69 files changed: 0 ins; 209 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/814.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/814/head:pull/814

PR: https://git.openjdk.java.net/jdk/pull/814