RFR: 8357434: x86: Simplify Interpreter::profile_taken_branch [v2]

[Aleksey Shipilev]

> Noticed that `Interpreter::profile_taken_branch` has the same `sbbptr` pattern we have eliminated with [JDK-8356946](https://bugs.openjdk.org/browse/JDK-8356946). The same logic applies here: the counter is 64-bit, never practically overflows, and no other code cares about it.
> 
> Also tidied up some comments around it.
> 
> Additional testing;
>  - [x] Linux x86_64 server fastdebug, `tier1 tier2`

Aleksey Shipilev has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:

 - Stale comment
 - Merge branch 'master' into JDK-8357434-x86-profile-taken
 - Fix

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/25343/files
  - new: https://git.openjdk.org/jdk/pull/25343/files/6dfa2db9..816b7af7

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25343&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25343&range=00-01

  Stats: 60495 lines in 967 files changed: 40475 ins; 14309 del; 5711 mod
  Patch: https://git.openjdk.org/jdk/pull/25343.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25343/head:pull/25343

PR: https://git.openjdk.org/jdk/pull/25343