RFR: 8281628: KeyAgreement : generateSecret intermittently not resetting

[Weijun Wang]

The comment said "pad it w/ leading 0s". So let's pad it.

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Commit messages:
 - remove x bits
 - 8281628: KeyAgreement : generateSecret intermittently not resetting

Changes: https://git.openjdk.java.net/jdk/pull/7665/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7665&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8281628
  Stats: 75 lines in 2 files changed: 74 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7665.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7665/head:pull/7665

PR: https://git.openjdk.java.net/jdk/pull/7665