RFR: Get rid of import of nsk.share.MainWrapper. It is no longer referenced.

[Chris Plummer]

This import of nsk.share.MainWrapper is the only current diff with mainline jdk. It is no longer needed after some wrapper related code was undone a while back.

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Commit messages:
 - Get rid of import of nsk.share.MainWrapper. It is no longer referenced.

Changes: https://git.openjdk.java.net/loom/pull/160/files
 Webrev: https://webrevs.openjdk.java.net/?repo=loom&pr=160&range=00
  Stats: 2 lines in 1 file changed: 0 ins; 1 del; 1 mod
  Patch: https://git.openjdk.java.net/loom/pull/160.diff
  Fetch: git fetch https://git.openjdk.java.net/loom pull/160/head:pull/160

PR: https://git.openjdk.java.net/loom/pull/160