RFR(S): 8156922: [ppc] Implement template interpreter stack overflow checks as on x86/sparc.

[Lindenmaier, Goetz]

HI Dean, 

> OK, looking at just your change, I had the following comments.  Overall, the
> changes look reasonable
> to me, for pcc.  But it seems that after this change, _stack_overflow_limit is
> only used by ppc.
> - Do you think it should be made a cpu-specific field?  Or do you think
> x86/sparc should use it as well?
Yes, as it saves a lot of instructions.  This could be done in a follow up change.
> - Do you think its value should be updated when the yellow/reserved zones
> are unprotected? 
Yes, but this should only be done after the above change has been applied
to all platforms.

Best regards,
  Goetz.