RFR: 8276166: Remove dead code from MimeTable and MimeEntry

[Сергей Цыпанов]

There are unused methods/constructors in mentioned classes that can be safely removed.

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Commit messages:
 - 8276166: Remove dead code from MimeTable and MimeEntry

Changes: https://git.openjdk.java.net/jdk/pull/6169/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6169&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8276166
  Stats: 45 lines in 2 files changed: 0 ins; 41 del; 4 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6169.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6169/head:pull/6169

PR: https://git.openjdk.java.net/jdk/pull/6169