[jdk8u-dev] RFR: 8173072: zipfs fails to handle incorrect info-zip "extended timestamp extra field"

[Xin Liu]

Package nio.zipfs is in demo directory of jdk8u. It is not the part of standard libraries until jdk9. However, we found that some Java8 applications use it and hit a bug. I guess this manifests Hyrum's Law again. 

This patch can *NOT* apply to jdk8u cleanly. I need to adjust the directory. I drop the cosmetic changes in nio/zipfs/ZipCoder.java. It helps minimize changeset. If we want to include them, we need to backport other patches. 

We test jtreg locally. I reckon the risk is minimal because the patch only adds a few boundary checks in nio/zipfs/EXTT. Without it, zipfs throws java.lang.ArrayIndexOutOfBoundsException when it encounters a problematic zip file.

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Commit messages:
 - Backport 248778d27a5f8a16e4c90a4f5a6632a7ca8e9a89

Changes: https://git.openjdk.org/jdk8u-dev/pull/349/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=349&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8173072
  Stats: 4 lines in 1 file changed: 1 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk8u-dev/pull/349.diff
  Fetch: git fetch https://git.openjdk.org/jdk8u-dev.git pull/349/head:pull/349

PR: https://git.openjdk.org/jdk8u-dev/pull/349