RFR JDK-8194084: Obsolete FastTLABRefill and remove the related code

[JC Beyler]

Hi all,

Here is a webrev to do the work mentioned in JDK-8194084
<https://bugs.openjdk.java.net/browse/JDK-8194084>:
http://cr.openjdk.java.net/~jcbeyler/8194084/webrev.01/

It has the parts for each architecture and I can't test a lot of them so I
would need a review and test for each :). I think first would be an
agreement to the code change itself then test it once everyone agrees on
the change ?

Could I please get some initial reviews on this?

Basically what this webrev does is follow what the interpreter is saying:
  - No longer try to do a fast tlab refill
  - Try eden allocation if contiguous inline allocation is true
  - Otherwise slowpath

This is true for all architectures except:
   - ppc, which doesn't do eden allocations, I just cleaned up the code a
bit there to be consistent
   - s390 that does not do tlab_refill at all, I just removed the dead code
there.

Thanks a lot for your help,
Jc