RFR: 8305201: Improve error message for GroupLayouts that are too large on SysV

[Jorn Vernee]

Using for instance a struct layout that contains an unbounded array will produce the exception from the JBS issue.

This patch checks for the case where a GroupLayout is too large more explicitly, and reports the issue using a more informative exception.

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Depends on: https://git.openjdk.org/jdk/pull/13079

Commit messages:
 - Add test. Use toIntExact
 - improve error message for too large structs

Changes: https://git.openjdk.org/jdk/pull/13581/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13581&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8305201
  Stats: 27 lines in 2 files changed: 24 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/13581.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13581/head:pull/13581

PR: https://git.openjdk.org/jdk/pull/13581