RFR: 8253822: Remove unused exception_address_is_unpack_entry

[Nils Eliasson]

I have searched the code base without finding any use.

Please review,

Best regards,
Nils

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Commit messages:
 - Remove unused exception_address_is_unpack_entry

Changes: https://git.openjdk.java.net/jdk/pull/410/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=410&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8253822
  Stats: 4 lines in 1 file changed: 0 ins; 4 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/410.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/410/head:pull/410

PR: https://git.openjdk.java.net/jdk/pull/410