RFR: 8342919: GenShen: Fix whitespace

[William Kemper]

There is an errant new line at the start of shFreeset.hpp.

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Commit messages:
 - Fix whitespace

Changes: https://git.openjdk.org/shenandoah/pull/524/files
  Webrev: https://webrevs.openjdk.org/?repo=shenandoah&pr=524&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8342919
  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/shenandoah/pull/524.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah.git pull/524/head:pull/524

PR: https://git.openjdk.org/shenandoah/pull/524