RFR: 8223051: support loops with long (64b) trip counts [v2]

[Roland Westrelin]

> Last webrev was:
> 
> https://cr.openjdk.java.net/~roland/8223051/webrev.03/
> 
> This PR includes a few minor changes:
> 
> - The change in callnode.cpp that Vladimir requested in:
>   https://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2020-August/039551.html
> 
> - Extra comments that John requested in:
>   https://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2020-August/039621.html
> 
> - A couple extra counters to collect more detailed statistics
> 
> 8252696 (Loop unswitching may cause out of bound array load to be
> executed) was the only bug that was uncovered by extended testing and
> it's fixed now.
> 
> This was previously reviewed by Tobias, Vladimir and John. Given the
> last changes were either requested by reviewers or a straighforward
> improvement to statistics, and unless someone objects, I intend to
> push this in the next few days with the reviewer list I just
> mentioned.

Roland Westrelin has updated the pull request with a new target base due to a merge or a rebase. The pull request now
contains two commits:

 - trailing whitespaces
 - long counted loops

-------------

Changes: https://git.openjdk.java.net/jdk/pull/318/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=318&range=01
  Stats: 902 lines in 11 files changed: 823 ins; 63 del; 16 mod
  Patch: https://git.openjdk.java.net/jdk/pull/318.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/318/head:pull/318

PR: https://git.openjdk.java.net/jdk/pull/318