RFR: JDK-8278273: Remove unnecessary exclusion of doclint accessibility checks

[Joe Darcy]

Exploratory builds indicate it is not currently necessary to exclude the doclint accessibility checks; this patch enables them.

(Enabling the reference checks is left for future work.)

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Commit messages:
 - JDK-8278273: Remove unnecessary exclusion of doclint accessibility checks

Changes: https://git.openjdk.java.net/jdk/pull/6713/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6713&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8278273
  Stats: 14 lines in 7 files changed: 0 ins; 0 del; 14 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6713.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6713/head:pull/6713

PR: https://git.openjdk.java.net/jdk/pull/6713