RFR: 8263974: Move SystemDictionary::verify_protection_domain

[Coleen Phillimore]

Please review this mostly trivial fix to move SystemDictionary::validate_protection_domain into Dictionary and hide the functions in Dictionary that it calls.  This change also removes some #include dictionary.hpp and a TRAPS parameter where not needed.

See CR for more details.  This function was in the middle of others that I want to keep together in systemDictionary.cpp.

Tested with tier1 on 4 Oracle supported platforms.

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Commit messages:
 - move some functions back, delete equals function.
 - 8263974: Move SystemDictionary::verify_protection_domain

Changes: https://git.openjdk.java.net/jdk/pull/3120/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3120&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8263974
  Stats: 175 lines in 8 files changed: 80 ins; 85 del; 10 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3120.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3120/head:pull/3120

PR: https://git.openjdk.java.net/jdk/pull/3120