RFR: 8256002: Cleanup of Wrapper changes

[Roger Riggs]

Cleanup of commit deprecating for removal the primitive wrapper classes.
 - Removed the unneeded test.
 - Restored the original code in some graal tests to avoid merge problems.
 - Removed unnecessary use of valueOf, when implicit casts were sufficient (in RMI classes).
 - Added a few SuppressWarnings for "removal" and "synchronization" to keep tests working.

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Commit messages:
 - Suppress removal and synchronization warning and make JapaneseDate fields final
 - 8256002: Cleanup of Wrapper changes

Changes: https://git.openjdk.java.net/valhalla/pull/268/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=268&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8256002
  Stats: 79 lines in 8 files changed: 1 ins; 62 del; 16 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/268.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/268/head:pull/268

PR: https://git.openjdk.java.net/valhalla/pull/268