[lworld] RFR: 8348585: [lworld] ProcessReaper stack size too small

[Roger Riggs]

The reaper stack size is insufficient to initialize the method handles for the equals methods of the primitive classes.
Instead of incrasing the stack size, perform the initialization before the reaper thread is created.

An earlier change to increase the stack only for a debug build is reverted, it is no longer needed.

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Commit messages:
 - 8348585: [lworld] ProcessReaper stack size too small

Changes: https://git.openjdk.org/valhalla/pull/1339/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1339&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8348585
  Stats: 7 lines in 1 file changed: 4 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/valhalla/pull/1339.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1339/head:pull/1339

PR: https://git.openjdk.org/valhalla/pull/1339