[master] RFR: 8304690: [Lilliput] Increase size of C2HandleAnonOMOwnerStub on x86

[Roman Kennke]

Deeper testing has revealed that the C2HandleAnonOMOwnerStub can take 18 bytes instead of currently used 17. We shall increase the max_size() for that stub. I haven't seen it on any of my machines, but it came up in testing of [JDK-8291555](https://bugs.openjdk.org/browse/JDK-8291555) in Oracle's testing infra. It's probably rare and/or machine dependent.

Testing:
 - [x] tier1

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Commit messages:
 - 8304690: [Lilliput] Increase size of C2HandleAnonOMOwnerStub on x86

Changes: https://git.openjdk.org/lilliput/pull/82/files
 Webrev: https://webrevs.openjdk.org/?repo=lilliput&pr=82&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8304690
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/lilliput/pull/82.diff
  Fetch: git fetch https://git.openjdk.org/lilliput.git pull/82/head:pull/82

PR: https://git.openjdk.org/lilliput/pull/82