RFR: 8294772: Remove workaround in os::dll_address_to_library_name

[Johan Sjölen]

I ported the BSD implementation of this function. According to the comment this bug should be fixed, as the oldest glibc I can see us supporting is 2.12.x. I've made an attempt at finding the bug that the comment refers to on glibc's bug tracker but has been unsuccesful in this.

The second commit deletes what seems like an outdated comment (in os_bsd this refers to a code snippet right below the comment).

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Commit messages:
 - Delete copy-pasted comment
 - We should be on glibc > 2.3 for a long time now

Changes: https://git.openjdk.org/jdk/pull/10559/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10559&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8294772
  Stats: 71 lines in 1 file changed: 0 ins; 67 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/10559.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10559/head:pull/10559

PR: https://git.openjdk.org/jdk/pull/10559