RFR: 8328614: hsdis: dlsym can't find decode symbol

[Robbin Ehn]

Hi, please consider.

[8327045](https://bugs.openjdk.org/browse/JDK-8327045) hide these symbols.
Tested with gcc and clang, and llvm and binutils backend.

I didn't find any use of the "DLL_ENTRY", so I removed it.

Thanks, Robbin

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Commit messages:
 - export symbols

Changes: https://git.openjdk.org/jdk/pull/18400/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18400&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8328614
  Stats: 17 lines in 4 files changed: 10 ins; 2 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/18400.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18400/head:pull/18400

PR: https://git.openjdk.org/jdk/pull/18400