RFR: 8289780: Remove Forte::register_stub [v2]

[Ioi Lam]

> I removed `Remove Forte::register_stub` since it's used only by the Solaris Forte(TM) Performance Tools collector, which is no longer supported by the JDK.
> 
> I also fixed a couple of places where the stub name is computed unnecessarily.
> 
> Also renamed some `#ifndef IA64` around the code that I touched.

Ioi Lam has updated the pull request incrementally with one additional commit since the last revision:

  Do not remove Forte::register_stub as it is used on Linux as well

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/9386/files
  - new: https://git.openjdk.org/jdk/pull/9386/files/a1523c9d..609350f1

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9386&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9386&range=00-01

  Stats: 117 lines in 7 files changed: 111 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/9386.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9386/head:pull/9386

PR: https://git.openjdk.org/jdk/pull/9386