RFR: JDK-8261447: MethodInvocationCounters frequently run into overflow

[Lutz Schmidt]

Dear community,
may I please request reviews for this fix, improving the usefulness of method invocation counters.
- aggregation counters are retyped as uint64_t, shifting the overflow probability way out (185 days in case of a 1 GHz counter update frequency).
- counters for individual methods are interpreted as (unsigned int), in contrast to their declaration as int. This gives us a factor of two before the counters overflow.
- as a special case, "compiled_invocation_counter" is retyped as long, because it has a higher update frequency than other counters.
- before/after sample output is attached to the bug description. 

Thank you!
Lutz

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Commit messages:
 - JDK-8261447: MethodInvocationCounters frequently run into overflow

Changes: https://git.openjdk.java.net/jdk/pull/2511/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2511&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8261447
  Stats: 184 lines in 8 files changed: 89 ins; 3 del; 92 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2511.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2511/head:pull/2511

PR: https://git.openjdk.java.net/jdk/pull/2511