RFR: 8330198: Add some class loading related perf counters to measure VM startup [v6]

[Calvin Cheung]

> Adding a few perf counters related to class loading to measure VM startup. The counters are only active if the user specifies `-Xlog:init` in the command line. A diagnostic flag `ProfileClassLinkage` is added to control the new counters. The flag is set to false by default and will be enabled if `-Xlog:init` is specified.
> 
> This change is already in the leyden/premain branch. There are more counters in the branch to measure other stuff. For now, just upstreaming class loader related counters.
> 
> Refer to the [comment](https://bugs.openjdk.org/browse/JDK-8330198?focusedId=14665311&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14665311) in the bug report for an example output.
> 
> Passed tiers 1 - 4 testing.

Calvin Cheung has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 10 commits:

 - @iwanowww comments
 - Merge branch 'master' into xloginit-classloading
 - more comments from @dholmes-ora
 - @dholmes-ora comments
 - comments from Ioi
 - Merge branch 'master' into xloginit-classloading
 - fix build issues on macos-x64 and -aarch64
 - Merge branch 'master' into xloginit-classloading
 - fix linux-x86 and minimal build issues
 - 8330198: Add some class loading related perf counters to measure VM startup

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Changes: https://git.openjdk.org/jdk/pull/18790/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18790&range=05
  Stats: 172 lines in 15 files changed: 157 ins; 6 del; 9 mod
  Patch: https://git.openjdk.org/jdk/pull/18790.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18790/head:pull/18790

PR: https://git.openjdk.org/jdk/pull/18790