[master] RFR: 8370258: Lilliput2: java/lang/instrument/GetObjectSizeIntrinsicsTest fails

[Y. Srinivas Ramakrishna]

Adjusted header size defined in test so that it's right for Lilliput2.

### Testing

Tested +/- UCOH release/fastdebug

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Commit messages:
 - Fix test defined constant for case of +UCOH in

Changes: https://git.openjdk.org/lilliput/pull/204/files
  Webrev: https://webrevs.openjdk.org/?repo=lilliput&pr=204&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8370258
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/lilliput/pull/204.diff
  Fetch: git fetch https://git.openjdk.org/lilliput.git pull/204/head:pull/204

PR: https://git.openjdk.org/lilliput/pull/204