RFR: 8344565: SM cleanup in jdk/internal and java/lang package private classes

[Roger Riggs]

SM removal for internal implementation classes: 
    java.lang.CharacterName
    java.lang.ref.Finalizer
    jdk.internal.icu.impl.ICUBinary
    jdk.internal.misc.ExtendedMapMode

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Commit messages:
 - Refactored to remove additional doPrivileged calls
 - 8344565: SM cleanup in jdk/internal packages

Changes: https://git.openjdk.org/jdk/pull/22370/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22370&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8344565
  Stats: 40 lines in 4 files changed: 0 ins; 23 del; 17 mod
  Patch: https://git.openjdk.org/jdk/pull/22370.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22370/head:pull/22370

PR: https://git.openjdk.org/jdk/pull/22370