RFR: 6227536: KeyGenerator.init() methods do not throw IllegalArgumentException for keysize == 0

[Kevin Driver]

As mentioned in the bug report, this issue *should not* be a framework-level issue, since potentially an individual provider could create a keysize of zero to have a certain significance. 

In the changes made here, the check is for `keysize <= 0` and this message indicates this is a check characteristic to the `SunJCE` provider.

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Commit messages:
 - update copyrights
 - initial commit

Changes: https://git.openjdk.org/jdk/pull/9679/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9679&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-6227536
  Stats: 12 lines in 2 files changed: 10 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/9679.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9679/head:pull/9679

PR: https://git.openjdk.org/jdk/pull/9679