[lworld] RFR: 8348428: [lworld] ProcessReaper stack size too small in debug build

[Roger Riggs]

Increase process reaper debug stack size to 64kb

Some tests of the fastdebug Java Runtime with -Xcomp experience a StackOverflow exception in the ProcessReaper in ProcessHandleImpl.
Some combination of -Xcomp and the MH generation done by isSubstitutability for value objects in debug mode is larger.

The current 16kb bump for the non-release builds should be raised to 64k.

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Commit messages:
 - 8348428: [lworld] ProcessReaper stack size too small in debug build

Changes: https://git.openjdk.org/valhalla/pull/1335/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1335&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8348428
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/valhalla/pull/1335.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1335/head:pull/1335

PR: https://git.openjdk.org/valhalla/pull/1335