RFR: 8310027: Fix -Wconversion warnings in nmethod and compiledMethod related code

Fri Jun 16 12:41:09 UTC 2023

This change adds casts to nmethod and compiled method offset and size functions that return int, and checked_casts where it's not obvious or already checked that the cast is correct.
Tested with tier1 on Oracle platforms, and tier1-4 linux and windows.

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Commit messages:
 - 8310027: Fix -Wconversion warnings in nmethod and compiledMethod related code

Changes: https://git.openjdk.org/jdk/pull/14505/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14505&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8310027
  Stats: 50 lines in 8 files changed: 0 ins; 0 del; 50 mod
  Patch: https://git.openjdk.org/jdk/pull/14505.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14505/head:pull/14505

PR: https://git.openjdk.org/jdk/pull/14505