RFR: 8314265: Fix -Wconversion warnings in miscellaneous runtime code [v6]

[Coleen Phillimore]

> Fix MaxElementPrintSize and casts. Also fixed miscellaneous -Wconversion warnings in runtime code.  This is the last one I'm going to do for runtime for a while.
> Tested with tier1-4.

Coleen Phillimore has updated the pull request incrementally with one additional commit since the last revision:

  Change size of op_index back.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/15233/files
  - new: https://git.openjdk.org/jdk/pull/15233/files/913d94ea..570823b0

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15233&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15233&range=04-05

  Stats: 8 lines in 2 files changed: 1 ins; 0 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/15233.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15233/head:pull/15233

PR: https://git.openjdk.org/jdk/pull/15233