RFR: 8312077: Fix signed integer overflow, final part

[Dean Long]

This is hopefully the last set of integer overflow fixes for hotspot.  Some of the counters I changed to unsigned are updated in platform-specific code, so I could use some help testing on arm, ppc,  riscv, and s390.

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Commit messages:
 - uint
 - use unsigned
 - counters are uint
 - make some counters unsigned
 - misc overflow fixes

Changes: https://git.openjdk.org/jdk/pull/14883/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14883&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8312077
  Stats: 310 lines in 25 files changed: 3 ins; 0 del; 307 mod
  Patch: https://git.openjdk.org/jdk/pull/14883.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14883/head:pull/14883

PR: https://git.openjdk.org/jdk/pull/14883