RFR: 8258796: [test] Apply HexFormat to tests for java.security

[Roger Riggs]

Followup to the addition of java.util.HexFormat.  
Uses of adhoc hexadecimal conversions are replaced with HexFormat.
Redundant utility methods are modified or removed.
In a few places the data being printed is ASN.1 and the test utility HexPrinter with the ASNFormatter is added.

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Commit messages:
 - 8258796: [test] Apply HexFormat to tests for java.security

Changes: https://git.openjdk.java.net/jdk/pull/2006/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2006&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8258796
  Stats: 738 lines in 43 files changed: 81 ins; 466 del; 191 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2006.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2006/head:pull/2006

PR: https://git.openjdk.java.net/jdk/pull/2006