RFR: 8310332: Fix -Wconversion warnings in MethodData

[Coleen Phillimore]

Please review this change to narrow parameter and return types to avoid implicit casts, add casts where obvious, add checked_cast<> where not obvious and changed the size of a couple parameters to not cast to the smaller size.
I didn't change TypeProfileWidth and BciProfileWidth because jvmci and SA care about the sizes.
Tested tier1 all Oracle supported platforms, and tier1-4 linux + windows x64.

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Commit messages:
 - Fix -Wconversion warnings in methodData

Changes: https://git.openjdk.org/jdk/pull/14557/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14557&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8310332
  Stats: 24 lines in 3 files changed: 0 ins; 0 del; 24 mod
  Patch: https://git.openjdk.org/jdk/pull/14557.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14557/head:pull/14557

PR: https://git.openjdk.org/jdk/pull/14557