RFR: JDK-8267930: Refine code for loading hsdis library

[Hamlin Li]

code for loading hsdis library is redundant, this is to simplify it.

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Commit messages:
 - JDK-8267930: Refine code for loading hsdis library

Changes: https://git.openjdk.java.net/jdk/pull/4260/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4260&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8267930
  Stats: 42 lines in 2 files changed: 12 ins; 25 del; 5 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4260.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4260/head:pull/4260

PR: https://git.openjdk.java.net/jdk/pull/4260