RFR: 8255529: Remove unused methods from java.util.zip.ZipFile

[Lance Andersen]

Please review this fix for JDK-8255529 which removes methods that were unused and were added back merge in July

Mach5 jdk-tier1, jdk-tier2, jdk-tier3 ran clean.

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Commit messages:
 - Remove unused methods

Changes: https://git.openjdk.java.net/jdk/pull/1015/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1015&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8255529
  Stats: 12 lines in 1 file changed: 0 ins; 12 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1015.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1015/head:pull/1015

PR: https://git.openjdk.java.net/jdk/pull/1015