RFR: 8337683: Fix -Wconversion problem with arrayOop.hpp

[Coleen Phillimore]

Since base_offset_in_bytes and HeapWordSize are int, there's no loss of conversion in making these variables int.  This seems trivial.
Tested with tier1 on linux and windows.

-------------

Commit messages:
 - 8337683: Fix -Wconversion problem with arrayOop.hpp

Changes: https://git.openjdk.org/jdk/pull/20431/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20431&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8337683
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/20431.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20431/head:pull/20431

PR: https://git.openjdk.org/jdk/pull/20431