RFR: 8266017: Refactor the *klass::array_klass_impl code to separate the non-exception-throwing API [v2]

[David Holmes]

> We currently have array_klass() and array_klass_or_null(), where the former can throw exceptions and the latter can not. But they both delegate to:
> 
> array_klass_impl(bool or_null, TRAPS)
> 
> which combines both the exception-throwing and non-exception-throwing code into one method declared with TRAPS. To make progress with the change of TRAPS to JavaThread (JDK-8252685) we need to separate these code paths into distinct methods.
> 
> Testing: tiers 1-3 (in progress)
> 
> Thanks,
> David

David Holmes has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains three commits:

 - Merge
 - Feedback from Ioi and Coleen: make the base API pure virtual and override those methods
   directly, getting rid of the impl versions,
 - 8266017: Refactor the *klass::array_klass_impl code to separate the non-exception-throwing API

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

Changes: https://git.openjdk.java.net/jdk/pull/3711/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3711&range=01
  Stats: 136 lines in 8 files changed: 65 ins; 51 del; 20 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3711.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3711/head:pull/3711

PR: https://git.openjdk.java.net/jdk/pull/3711