[master] RFR: 8303816: [Lilliput] Use realloc instead of malloc+copy when growing the lock-stack

[Roman Kennke]

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We currently grow the fast-locking lock-stack by allocating a larger stack and copying over all elements. This can be done simpler and more efficient by using realloc instead of malloc+copy.

I also applied the same change to the upstream fast-locking PR: https://github.com/openjdk/jdk/pull/10907

Testing:
 - [x] tier1

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Commit messages:
 - 8303816: [Lilliput] Use realloc instead of malloc+copy when growing the lock-stack

Changes: https://git.openjdk.org/lilliput/pull/79/files
 Webrev: https://webrevs.openjdk.org/?repo=lilliput&pr=79&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8303816
  Stats: 6 lines in 1 file changed: 0 ins; 5 del; 1 mod
  Patch: https://git.openjdk.org/lilliput/pull/79.diff
  Fetch: git fetch https://git.openjdk.org/lilliput pull/79/head:pull/79

PR: https://git.openjdk.org/lilliput/pull/79